Blog List

Thursday, 2 June 2016

Estimation of demand for wood panels in Iran by the year of 2012

Published Date
, Volume 20, Issue 2, pp 179-182
First online: 

Title

Estimation of demand for wood panels in Iran by the year of 2012


  • Author 
  • Majid Azizi 
  • , Payam Ghorbannezhad
  • , Hamid Hatefnia

    Abstract
  • Considering increasing rate of Iran population and consumption of wood panels, the authors investigated the per capita consumption of wood panels during the years from 1997 to 2007. The exponential smoothing method was used to obtain a per capita consumption pattern of wood panels in Iran for estimating demand of wood panels by the year of 2012. Results show that the consumption of particleboard, fiberboard, and medium density fiberboard in Iran will increase by 33%, 72% and 107 %, respectively, by the year of 2012; however, the consumption of plywood will increase only by 7% by 2012. The deficient amount of wood panels in Iran is estimated over 1400 000 m3. The results of this study provide the technique reference for planners of wood panel industries in Iran in capital investment decisions.

    Keywords

    wood panels exponential smoothing estimating Iran wood panel demand
    References 

  1. Alexander K, Handfield RB. 2003. An industrial application of time series forecasting of lumber demand (M.Sc thesis). Carolina State: North Carolina State University publication, p87.
  2. Amiri S. 1990. Review the production and import of wood in Iran. Iran Natural Resources Journal, 44: 39–56.
  3. Azizi M. 2008. A model of supplying poplar wood for Iranian paper & wood factories. Journal of Forestry Research, 19(4): 323–328.CrossRef
  4. Azizi M, Faezipour M. 2006. Consumption forecasting of Iran plywood industry with respect to its substitution rate building applications. Journal of Applied Science, 6(5): 1040–1046.CrossRef
  5. Billah B, King LM, Snyder DR, Koehler BA. 2006. Exponential smoothing model selection for forecasting. International journal of forecasting, 22: 239–247.CrossRef
  6. Frazier GD. 1965. Estimated demand for lumber and plywood in Hawaii by the year 2000 (Res. Paper PSW-RP-23. Berkeley, Forest Service). U.S.: U.S. Department of Agriculture publication, p9.
  7. Gardner ES. 1998. Exponential smoothing: The state of the art. Journal of forecasting, 4: 1–28.CrossRef
  8. Howard JL. 2001. Timber production, trade, consumption, and price statistics 1965 to 1999 (Res.Pap.FPL-RP-595, technical report). USDA: USDA publication, p76.
  9. Makridakis S, Andersen A, Carbone R, Fildes R, Hibon M, Lewandowski R, et al. 1982. The accuracy of extrapolation (time series) methods: results of forecasting competition. Journal of Forecasting, 1: 111–153.CrossRef
  10. Makridakis S, Hibon M. 2000. The m3-competition: results, conclusions and implications. International Journal of Forecasting, 16: 451–476.CrossRef
  11. Makridakis S, Wheelwright SC, Hyndman RJ. 1998. Forecasting: methods and applications (3rd ed). New York: John Willey & Sons publication, p994.

  • For further details log on website :
at No comments:

Production, characterization and prediction of mechanical properties of waste fibre reinforced composite panels for application in adjustable partition walls of buildings

Published Date
, Volume 19, Issue 1, pp 153-166
First online: 

Title 

Production, characterization and prediction of mechanical properties of waste fibre reinforced composite panels for application in adjustable partition walls of buildings

  • Author 
  • J. Velosa
  • , S. Rana 
  • , R. Fangueiro
  • , P. Mendonça

    Abstract
  • In the present paper, waste fibre reinforced composite panels have been developed for application in interior partition walls of buildings. These panels were produced using waste fibres collected from the textile industries and using aminoplastic phenol-formaldehyde resin. Mechanical properties such as tensile, compression and flexural properties of these composite panels were characterized and the influence of a few parameters such as fibre or matrix weight % and composite density on the mechanical properties has been analyzed. Impact properties (soft body and hard body impact), which is very important for the materials used in the partition walls, of the developed composite panels was simulated using finite element method and the influence of composite parameters (fibre or resin content, composite density) on the impact resistance and strain energy was analyzed. Thermal degradation behaviour of the developed composite panels was also investigated. Although the waste fibre reinforced composites show low mechanical properties, the simulation results showed that the composite panels showed required impact properties (no collapse, no penetration or projection under both soft and hard body impact) for their successful application in the interior partition walls. Thermal stability of the composite panels was also sufficient for this application. It was also observed that the composite panels exhibited better impact resistance and lower deformation when produced with higher fibre % as well as higher density.

    Keywords

    Waste fibre composites Mechanical properties Thermal stability Impact resistance Finite element method

    • References 
        1. 1.
          ETAG_003 (1998) Guideline for European technical approval for internal partition kits for use as non-loadbearing wall
        2. 2.
          EOTA (2003) Determination of impact resistance of panels and panel assemblies, technical report TR 001
        3. 3.
          EN1991-1-1-Eurocode-1 (2001) Actions on structures - part 1–1: general actions – densities, self-weight, imposed loads for buildings
        4. 4.
          Horden R (1995) Light tech: towards a light architecture. Birkhauser Verlag AG, Berlin
        5. 5.
          Slessor C, Linden J (1997) Eco-tech: sustainable architecture and high technology. Thames and Hudson, New York
        6. 6.
          Mendonca P (2005) Living under a second skin—strategies for environmental impact reduction for solar passive constructions in temperate climates. PhD Thesis, Portugal
        7. 7.
          Fangueiro R (2011) Fibrous and composite materials for civil engineering applications. Woodhead Publishing Ltd, CambridgeCrossRef
        8. 8.
          Emori K, Kimura T (1999) Recyclability of glass cloth waste coated by PVC as a fiber reinforced composite. Proceedings of Recycling of Fibrous Textile and Carpet Waste Conference, Georgia Institute of Technology, USA
        9. 9.
          Gomes MG, Fangueiro R, Jobim G, Pereira CG (2006) Composite materials reinforced by waste fibers. Proceedings of Mechanics & materials in design—5 th Internacional Conference, Porto, Portugal
        10. 10.
          Jayaraman K, Bhattacharyya D (2004) Resour Conserv Recycl 41:307CrossRef
        11. 11.
          Savastano H Jr, Warden PG, Coutts RSP (2000) Cement Concr Compos 22:379CrossRef
        12. 12.
          Turner TA, Pickering SJ, Warrior NA (2011) Compos Part B 42:517CrossRef
        13. 13.
          Verma D, Gope PC, Maheshwari MK, Sharma RK (2012) J Mater Environ Sci 3:1079
        14. 14.
          Sivaraja M, Kandasamy S (2011) Asian J Civil Eng (Build Hous) 12:205
        15. 15.
          Heil JP, Cuomo JJ (2011) Recycling carbon fibre composites using injection moulding and resin transfer moulding. Proceedings of 16th International Conference on Composite Structures. Porto, Portugal
        16. 16.
          Ragoubia M, Bienaimé D, Molina S, George B, Merlin A (2010) Ind Crop Prod 31:344CrossRef
        17. 17.
          Parveen S, Rana S, Fangueiro R (2012) Natural fiber composites for structural applications. Proceedings of Mechanics of Nano. Micro and Macro Composite Structures, Torino, Italy
        18. 18.
          Thakur VK, Thakur MK, Raghavan P, Kessler MR (2014) ACS Sustain Chem Eng 2:1072CrossRef
        19. 19.
          Thakur VK, Thakur MK (2014) Carbohydr Polym 109:102–117CrossRef
        20. 20.
          Thakur VK, Thakur MK, Gupta RK (2014) Int J Polym Anal Charact 19:256CrossRef
        21. 21.
          Rana S, Pichandi S, Parveen S, Fangueiro R (2014) Natural plant fibers: production, processing, properties and their sustainability parameters. In: Muthu SS (ed) Roadmap to sustainable textiles and clothing: eco-friendly raw materials, technologies, and processing methods. Springer, Singapore, pp 1–35
        22. 22.
          Rana S, Pichandi S, Parveen S, Fangueiro R (2014) Regenerated cellulosic fibers and their implications on sustainability. In: Muthu SS (ed) Roadmap to sustainable textiles and clothing: eco-friendly raw materials, technologies, and processing methods. Springer, Singapore, pp 239–276
        23. 23.
          Rana S, Pichandi S, Parveen S, Fangueiro R (2014) Biosynthetic fibers: production, processing, properties and their sustainability parameters. In: Muthu SS (ed) Roadmap to sustainable textiles and clothing: eco-friendly raw materials, technologies, and processing methods. Springer, Singapore, pp 109–138
        24. 24.
          Rana S, Pichandi S, Parveen S, Fangueiro R (2014) Biodegradation studies of textiles and clothing products. In: Muthu SS (ed) Roadmap to sustainable textiles and clothing: environmental and social aspects of textiles and clothing supply chain. Springer, Singapore, pp 83–123
        25. 25.
          Zhang J, Wang X, Zhang S, Gao Q, Li J (2013) Bioresour 8:5500
        26. 26.
          GĂ¼rses A, Karagöz S, Mindivan F, GĂ¼neÅŸ K, DoÄŸar C, AktĂ¼rk S (2014) Acta Phys Pol A 125:368CrossRef
        27. 27.
          Singha AS, Thakur VK (2008) Iran Polym J 17:861
        28. 28.
          Singha AS, Thakur VK (2009) E- J Chem 6:71CrossRef
        29. 29.
          Singha AS, Thakur VK (2009) Polym Plast Technol Eng 48:482CrossRef
        30. 30.
          Singha AS, Thakur VK (2008) Int J Polym Mater 58:21CrossRef
        31. 31.
          Singha AS, Thakur VK (2010) Polym Compos 31:459
        32. 32.
          Velosa J, Rana S, Santos T, Fangueiro R, Ramos L (2013) Polym Polym Compos 21:387
        33. 33.
          Xing T, Liu J, Li S, Chen G (2012) Therm Sci 16:1472CrossRef

      • For further details log on website :
      at No comments:

      A simple route to develop transparent doxorubicin-loaded nanodiamonds/cellulose nanocomposite membranes as potential wound dressings.

      Published Date
      Carbohydr Polym. 2016 Jun 5;143:231-8. doi: 10.1016/j.carbpol.2016.01.076. Epub 2016 Feb 2.

       Title 
      A simple route to develop transparent doxorubicin-loaded nanodiamonds/cellulose nanocomposite membranes as potential wound dressings.

      Author
      Luo X1, Zhang H2, Cao Z2, Cai N2, Xue Y2, Yu F3.


      Abstract

      The objective of this study is to develop transparent porous nanodiamonds/cellulose nanocomposite membranes with controlled release of doxorubicin for potential applications as wound dressings, which were fabricated by tape casting method from dispersing carboxylated nanodiamonds and dissolving cellulose homogeneously in 7wt% NaOH/12wt% urea aqueous solution. By adjusting the carboxylated nanodiamonds content, various nanocomposite membranes were obtained. The structure and properties of these membranes have been investigated by light transmittance measurements, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), tensile tests, water loss analyses, etc. The drug loading and release was investigated using doxorubicin hydrochloride as a model drug. In vitro cytotoxicity assay of the membranes was also studied. This work presented a proof-of-concept utility of these membranes for loading and release of bioactive compounds to be employed as a candidate for wound dressing.


      For further details log on website :

      http://www.ncbi.nlm.nih.gov/pubmed?cmd=search&term=27083364
      at No comments:

      Characterization of Corn Starch Films Reinforced with CaCO3 Nanoparticles

      Title
      Characterization of Corn Starch Films Reinforced with CaCO3 Nanoparticles

      Author
      • Published: September 4, 2014
      • http://dx.doi.org/10.1371/journal.pone.0106727

      Abstract


      The characterization of corn starch (CS) films impregnated with CaCO3 nanoparticles was investigated. Criteria such as morphology, crystallinity, water vapor permeability (WVP), opacity, and mechanical properties were the focus of the investigation. It was found that the CaCO3contents had significant effects on the tensile properties of the nanocomposite films. The addition of CaCO3 nanoparticles to the CS films significantly increased tensile strength from 1.40 to 2.24 MPa, elongation from 79.21 to 118.98%, and Young’s modulus from 1.82 to 2.41 MPa. The incorporation of CaCO3 nanoparticles increased the opacity of films, lowered the degree of WVP and film solubility value compared to those of the CS films. The results of scanning electron microscopy (SEM) showed that with the increase of CaCO3 nanoparticles content in starch films, the roughness of the films increased, and pores or cavities were found on the surface of the films, while small cracks were observed in the structures of the fractured surfaces. X-ray diffraction showed that the addition of nanoparticles increased the peaks in the intensity of films.
      Citation: Sun Q, Xi T, Li Y, Xiong L (2014) Characterization of Corn Starch Films Reinforced with CaCO3 Nanoparticles. PLoS ONE 9(9): e106727. doi:10.1371/journal.pone.0106727
      Editor: Miklos S. Kellermayer, Semmelweis University, Hungary
      Received: April 3, 2014; Accepted: August 8, 2014; Published: September 4, 2014
      Copyright: © 2014 Sun et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
      Data Availability: The authors confirm that all data underlying the findings are fully available without restriction. All data are included within the paper.
      Funding: These authors have no support or funding to report.
      Competing interests: The authors have declared that no competing interests exist.

      Introduction


      Starch has received considerable attention because of its totally biodegradable nature, low cost and wide availability [1]–[4]. Starch has been considered one of the biopolymers with the greatest potential to produce biodegradable films by different processing techniques such as casting, injection or blow molding and so on [5]. Several studies have reported the use of starches from different sources as raw material for films and coatings with different properties, showing the potential of this carbohydrate in these application fields [6]–[7]. However, there are some strong limitations to developing starch based films, which have poor tensile properties and high water vapor permeability on account of their hydrophilic nature and their sensitivity to moisture content. One possible approach to overcome this limitation is to strengthen starch matrixes with organic or mineral fillers [8]. These fillers reinforce biopolymeric matrixes and lead to the development of films with special properties due to the synergic effect between the components [9].

      Nanoparticles are a new type of filler that show a higher level of efficiency in improving the physicochemical and mechanical properties of starch-based films. Nanoparticles have good compatibility with the matrix in the thermoplastic starch films [10]. The tensile and water barrier properties of cassava starch composite films are reinforced by synthetic zeolite and beidellite [11]. Besides, with the incorporation of the nanofiller, starch-based materials generally show improvement in thermal stability, oxygen barrier property, and biodegradation rate. [12]. Calcium carbonate (CaCO3) nanoparticles are a white powder and used as filler in composite materials, such as in plastics and in paper industry. However, there are no reports about starch films reinforced with CaCO3 nanoparticles.

      The aims of this work are to develop nanocomposite films based on corn starch with CaCO3nanoparticles and to evaluate the effect of filler addition on the mechanical properties and moisture resistance of corn starch/CaCO3 nanoparticles films.

      Materials and Methods

      Materials


      Corn starch (amylose content 26.33%) was purchased from the National Starch Co. (Shanghai, China) and we obtained the CaCO3 nanoparticles, which have a high purity (98%), from Hefei Aiwei Nano Science and Technology Co., Ltd (Anhui, China). Fig. 1 shows the morphology and size of CaCO3 nanoparticles and the size is 35±2 nm. Glycerol (analytical grade) was used as plasticizer.

      thumbnail
      Download:
      Figure 1. SEM micrographs (100000×) of CaCO3 nanoparticles.
      http://dx.doi.org/10.1371/journal.pone.0106727.g001

      Film preparation


      The method of preparation was adapted from Araujo-Farro et al. (2010) with some modifications [13]. Corn starch (7.5 g) and glycerol (3.0 g) were added to 100 ml distilled water to obtain composite solutions. CaCO3 nanoparticles were dissolved in 50 ml distilled water by ultrasonic mixing. The percentage of the CaCO3 nanoparticles used was set at 0, 0.02, 0.04, 0.06, 0.1 and 0.5% levels on the dry basis of corn starch, respectively. It was mixed with the starch/glycerol composite solutions. The mixture solutions were heated in a boiling water bath with continuous agitation for 30 min to allow full gelatinization of the corn starch. After the heating period, the composite solutions were degassed under a vacuum (0.1 MPa) for 10 min and cooled down to room temperature. The mixture (about 65 g) was then spread evenly over Petri dishes (15 cm diameter) and evaporated in a ventilated oven at 45°C for 48 h. All the dried starch films were preserved in a humidity chamber (25°C, RH = 53%) for further testing.

      Optical properties


      The transparency of the films was determined by measuring their light absorption at wavelength of 600 nm using a UV-Visible spectrophotometer Shimadzu 1601 PC (Tokyo, Japan), according to the method described by Maran et al. (2013) [14]. The film specimens were cut into strips (1×4 cm) and placed directly in the spectrophotometer test cell. Air was used as reference. Opacity was expressed as absorbance units per thickness unit. All of these samples were carried out in triplicate.

      Mechanical properties


      A TA. XT Plus Texture Analyzer (Lloyd Instruments, West Sussex, England) was used to determine the tensile strength and percentage of elongation at the break. Film specimens were tested as suggested by Mehyar et al. (2012) with some modifications and the tests were carried out according to the ASTM D828–97 standard test methods (ASTM, 1997) [15]. CS/CaCO3nanoparticles composite films were cut into strips (1×10 cm). The clamp distance was 20 mm and the draw rate was 100 mm/min. Tensile strength (MPa) was calculated by dividing the maximum load by a cross-sectional area of the film. Percentage of elongation at the break was expressed as a percentage of change of the original length of a specimen between grips at the break. Before the testing, the strips were preconditioned at 67% RH for 48 h at room temperature (25±1°C). All samples were carried out in triplicate.

      Measurement of water vapor permeability (WVP)


      Before the testing, the films were conditioned at 25°C for 48 h in a desiccator with a relative humidity of 67%. Circular film samples were placed over the mouth of the test cup and sealed by melted paraffin in the desiccator. The test cup was about 10 mm in diameter. Anhydrous calcium chloride (0% RH) was placed inside the test cup while a saturated sodium chloride solution (75% RH) was placed in the desiccator. The change in the weight of the cups was measured every 12 h over two days. The gravimetric method was used to determine WVP of CS/CaCO3 nanoparticles blend films as suggested by Liu et al. (2005). The WVP was calculated as follows:where d is film thickness (m), m is the weight increment of the cup (g), A is the area exposed (m2), t is the time lag for permeation (h), and P is water vapor partial pressure difference across the film (Pa). All samples were carried out in triplicate.

      Scanning electron microscopy (SEM)


      The films’ external surfaces and cross sections were observed with a JSM-5610LV SEM (JEOL, Tokyo, Japan), respectively, according to the description of De la Caba et al. (2012) and Garg et al. (2007) [16]–[17]. Prior to the observation, the external surfaces were sputter-coated with a gold layer. To observe the cross section, the films were frozen in liquid nitrogen and then fractured immediately. The fracture surfaces were sputtered with gold and then photographed.

      Differential scanning calorimetry (DSC) analysis


      DSC experiments were carried out using DSC1 (METTLER TOLEDO, Switzerland). The calorimeter was calibrated with indium (melting point 156.6°C, heat of fusion 28.5 J/g). The DSC runs were operated under nitrogen gas atmosphere (30 mL/min) and an empty pan was used as the reference. The film samples, approximately 3 mg, were hermetically sealed in aluminum pans. The pans were heated from 15°C to 300°C at the scanning rate of 10°C/min. The DSC thermograms were evaluated to characterize the onset, peak and end temperatures and the enthalpy changes of the phase transitions.

      X-ray diffraction


      The crystalline structure of the film samples was analyzed by Philips PW1710 (Philips, Holland), provided with a tube, a copper anode, and a detector operating at 45 kV and 30 mA within 2θ from 4 to 40° with a 0.02° step size.

      Statistical analysis


      The experiment data were subjected to statistical analysis using SPSS 17.0 (SPSS Inc., 160 Chicago, USA). The data were analyzed using analysis of variance (ANOVA) using the Origin Pro 7.5 statistics program and expressed as mean values ± standard deviation. Differences were considered at a significant level of 95% (p<0.05).

      Results and Discussion

      WVP and Optical properties of films


      The opacity of CS/CaCO3 nanoparticles composite films are shown in Table 1. The film opacity values were used to assess the transparency of the films. As we can see, the pure CS films had the lowest opacity. Film opacity increased significantly (p<0.05) with an increase in CaCO3nanoparticles concentration in corn starch formulations. A similar tendency was reported by Mbey et al. (2012) for cassava starch-kaolinite composite films; they reported that when talc was added to the plasticized cassava starch matrix, there was a reduction of transmittance [18]. The possible reason for higher opacity value in films is due to the fact that mean particle size of the nanoparticles is almost similar to the size of the interspaces in starch film. When the light passes through these films, a much lower extent of light is transmitted through the film, which results in higher opacity value [19]. Bodirlau et al. (2012) reported that the increase in ordered zones led to reduce absorbance and increase film transparency [20]. In general, higher light absorbance of films related to desirable properties of food packaging since it was an excellent barrier to prevent light-induced lipid oxidation.

      thumbnail
      Download:
      Table 1. Water vapor permeability (WVP) and optical properties of corn starch (CS) based films with CaCO3 nanoparticles (Ca)g.
      http://dx.doi.org/10.1371/journal.pone.0106727.t001

      The water vapor permeability (WVP) of corn starch/CaCO3 nanoparticles blend films is shown in Table 1. WVP of the films is important when it is applied as packaging materials. In such cases one of the functions of the film is to avoid, or at least to decrease, moisture transfer between the food and the surrounding atmosphere; WVP should be as low as possible. As can be seen from Table 1, the pure CS films had the highest WVP (5.36×10−10 g Pa−1 s−1m−1), which was significantly higher than starch composite films containing CaCO3 nanoparticles. When the content of CaCO3 nanoparticles was 0.06%, the blend films had the lowest value of WVP.

      The enhancement in water vapor resistance with the addition of CaCO3 nanoparticles can be due to their nanometric size, which increases the surface volume ratio and promotes a better dispersion of the nanoparticles in the starch matrix. The well distributed nanoparticles can generate a curved path and force water molecules to flow through the composite in a tortuous path, decreasing their diffusion through the film. In addition, the CaCO3 nanoparticles are less hydrophilic than starch, making the film more hydrophobic. Muller et al. (2011) have also observed a decrease in the WVP of the films caused by the incorporation of nanoclay; they attributed this behavior to the tortuous paths available for water vapor diffusion [21]. It had been previously reported that the nanoparticles could prevent the formation of hydrogen bonding between starch molecules, giving rise to a more compact structure with smaller inter-chain spaces that can reduce the water vapor diffusion through the film. In general, CS/CaCO3nanoparticles composites films showed better barriers to water vapor.

      Mechanical properties of the films


      The effect of CaCO3 nanoparticles content on mechanical properties is presented in Table 2. Food packaging generally requires resistance to high stress with deformation according to the intended application. The pure CS films had the lowest mechanical properties. The addition of CaCO3 significantly improved tensile strength, elongation at the break and Young’s modulus, which increased from 1.40 to 2.24 MPa, 79.21 to 118.98% and 1.82 to 2.41 MPa, respectively. The tensile strength of the films increased with the increasing of the CaCO3 nanoparticles content up to 0.06% and then decreased as the increasing of the nanoparticle content went on. It seemed as if loading more than 0.06% of the nanoparticles did not lead to a greater effect because of the phase separation between the nanoparticle aggregates and starch matrix. The results in this study were in line with Min Wu et al. (2009) who reported that SiO2 nanoparticles, as a filling agent, could effectively improve the tensile properties of starch films [22]. The increased mechanical properties might be attributed to the well dispersion state of nanoparticles and the interactions between CaCO3 nanoparticles and chain segments of corn starch, which reduced chain mobility and hence improved macroscopic rigidity of CS/CaCO3nanoparticles composite films. Chivrac (2008) reported that the nanocomposites exhibited a remarkable improvement in the mechanical properties especially in the Young’s modulus and this was due to the filler surface-polymer chain segments interactions which reduced chain mobility and hence improved macroscopic rigidity [23]. Nanofillers act efficiently as matrices reinforcement, but only if they are well dispersed, so the interface with the matrix would be maximized.

      thumbnail
      Download:
      Table 2. Mechanical properties of corn starch (CS) based films with CaCO3nanoparticles (Ca)g.
      http://dx.doi.org/10.1371/journal.pone.0106727.t002

      SEM image of CS/CaCO3 nanoparticles blend films


      The SEM image of CS/CaCO3 nanoparticles blend films is shown in Fig. 2. As can be seen from Fig. 2, the surface of starch film without nanoparticles was smooth, however, the films containing CaCO3 nanoparticles (Fig. 1b and c) showed roughness, especially on the films containing 0.5% content CaCO3 nanoparticles, which exhibited many protuberances or micro-scaled particles indicating the phase separation. The phase separation could weaken the interface adhesion between nanofiller and matrix leading to decreasing tensile strength of the films with higher content of the nanoparticles (Table 2). The tuber on the image suggested that the nanoparticles are uniformly scattered in the CS matrix. De Melo et al. (2011) stressed that the surfaces of starch-nanoclay films showed less smooth than that of the starch films [24]. The incorporation of nanoparticles resulted in a density network structure, which was a good indicator of high tensile strength as shown in Table 2.

      thumbnail
      Download:
      Figure 2. SEM micrograph from surface of corn starch (CS) films (a), composite films with (b) 0.06%, (c) 0.5% CaCO3 nanoparticles; and fracture of CS films (d), composite films with (e) 0.06%, (f) 0.5% CaCO3 nanoparticles.
      http://dx.doi.org/10.1371/journal.pone.0106727.g002

      The cross-section images of films prepared with different CaCO3 nanoparticles ratios are shown in Fig. 2. Pure starch films (Fig. 1d) showed a continuous and smooth aspect, indicating the integrity of the structure. This result was consistent with Mali et al. (2002), who reported that a compact and homogeneous matrix was observed in yam starch-based films with glycerol produced by casting [25]. The composite films with 0.06% CaCO3 nanoparticles (Fig. 1e) showed a rough fracture, while several micro-folds could be observed in the cross-section, which might be attributed to the small addition of nanoparticles. The films needed more energy and had larger tensile strength. Furthermore, the long and deep cracks could be found in 0.5% CaCO3 nanoparticles (Fig. 1f), which indicated the formation of a more fragile structure in these cases. The results may be due to molecular irregularity increasing with an increment of particle concentration.

      Thermal properties of nanoparticles/starch blends


      The effects of CaCO3 nanoparticles on the thermal properties of nanoparticles/starch blends were evaluated by DSC. Table 3 shows the thermal parameters of various starch/nanoparticles blend films.

      thumbnail
      Download:
      Table 3. Thermal properties of corn starch (CS) based films with CaCO3nanoparticles (Ca)g.
      http://dx.doi.org/10.1371/journal.pone.0106727.t003

      From Table 3, we observed that there was a single endothermic transition between 190 to 240°C. When CaCO3 nanoparticles were added to the films, the transition shifted to higher values. This change may be due to the presence of smaller and more irregular CaCO3nanoparticles in nanocomposites than those in the control films. Both onset and melting temperature of the nanocomposite films were higher than those of the corn starch films. The melting temperature of starch/nanoparticles blend films was highest in the presence of 0.06% CaCO3 nanoparticles. This could be due to the fact that the nanoparticles were well distributed in the starch matrix, which increased the contact area between the nanoparticles and the matrix and consequently increased the compact structure of the films, which required a higher temperature to disorganize. A similar reasoning was offered by Selene Aila-SuĂ¡rez et al. (2013) [26], who found that cellulose nanoparticles increased the contact area between both polysaccharides, requiring a higher temperature to melt the structure. The melting enthalpy of CS film was 36.07 J/g. Likewise, Selene Aila-SuĂ¡rez et al. (2013) also reported that the ΔH value of CS film was 28.25 J/g [26]. With the increase of CaCO3 nanoparticles, the melting enthalpy of films became higher than pure corn starch; this may be due to the interactions between CaCO3 nanoparticles and chain segments of corn starch, which increased the crystallinity of the film. It could be deduced that the higher the values of the melting enthalpy, the higher compatibility of CS/CaCO3 nanoparticles.

      Amorphous/crystalline nature


      The diffraction patterns of CaCO3 nanoparticles and corn starch films in the presence and absence of the nanoparticles in between 5°(2θ) and 40°(2θ) are shown in Fig. 3. As can be seen from Fig. 3, the X-ray diffraction pattern of the pure CS film presented low intensity, narrow diffraction peaks and low crystallinity. CS film spectra showed the main characteristic peaks at 5.6° and 17°. This diffraction pattern may be due to the strong interaction between hydroxyl groups of starch molecules that were substituted by hydrogen bonds formed between the plasticizer and starch during processing. However, the characteristic diffraction peaks of the nanocomposite films had slight changes compared to the CS matrix and pure CaCO3nanoparticles. The characteristic peaks of CS/CaCO3 nanoparticles film that can be detected at 5.6°, 17°, 19.5° and 22° assigned them to a B and V type structure. The peak of CaCO3nanoparticles at 17.5° disappeared in the nanocomposite films, that may be due to the good compatibility between corn starch and CaCO3 nanoparticles. A widening in the peaks can be observed in Fig. 3. Ungar (2004) stressed that a broadening X-ray peak indicated that crystal lattice became imperfect, according to the theory of kinematical scattering; otherwise, peak broadening is caused by small crystal size [27]. As was expected, the addition of nanoparticles modified the peak intensity of films, which became stronger than that of CS films.

      thumbnail
      Download:
      Figure 3. X-ray diffraction patterns spectra of CaCO3 nanoparticles (Ca) and corn starch (CS) films with 0, 0.02, 0.04, 0.06, 0.1, 0.5% w/w Ca.
      http://dx.doi.org/10.1371/journal.pone.0106727.g003

      Conclusions


      The mechanical properties (tensile strength, elongation at the break and Young’s modulus) increased with the addition of CaCO3 nanoparticles, indicating that CaCO3 nanoparticles could be used to greatly improve film strength and flexibility. When CaCO3 nanoparticles were added to CS the film at 0.06% level, the WVP of the films was significantly decreased. The result showed that the water barrier properties of the CS film were obviously improved by the incorporation with CaCO3 nanoparticles into CS films, suggesting that the smooth and compact structure between nanoparticles and CS was formed, which can be confirmed by the SEM image. The addition of nanoparticles increased the melting temperature of films by DSC. X-ray diffraction results showed that CaCO3 nanoparticles and corn starch matrix had good compatibility. Therefore, it can be concluded that the CaCO3 nanoparticles and CS would be an attractive method to develop new edible films. It was observed from this work that the content of CaCO3 nanoparticles at 0.06% may be the best option for the desirable properties of edible films.

      Acknowledgments


      We thank Ms. Hu and Ms. Dong (Central Laboratory, Qingdao Agricultural University) for their help with SEM and XRD analysis.

      Author Contributions

      Conceived and designed the experiments: QJS. Performed the experiments: QJS TTX. Analyzed the data: QJS TTX YL. Contributed reagents/materials/analysis tools: LX. Wrote the paper: QJS TTX.

      References

      1. 1.Lopez O, Garcia M, Zaritzky N (2008) Film forming capacity of chemically modified corn starches. Carbohydrate Polymers, 73, 573–581. doi: 10.1016/j.carbpol.2007.12.023 
      2. 2.Lopez O, Garcia M, Zaritzky N (2010) Novel sources of edible films and coatings. Postharvest Review, 6(3), 1–8. doi: 10.2212/spr.2010.3.2 
      3. 3.Lopez O, Garcia M, Zaritzky N (2010) Physicochemical characterization of chemically modified corn starches related to rheological behavior, retrogradation and film forming capacity. Journal of Food Engineering, 100(1), 160–168. doi: 10.1016/j.jfoodeng.2010.03.041 
      4. 4.Lopez O, Lecot C, Zaritzky N, Garcia M (2011) Biodegradable packages development from starch based heat sealable films. Journal of Food Engineering, 105(2), 254–263. doi: 10.1016/j.jfoodeng.2011.02.029 
      5. 5.Teixeira ED, Curvelo M, CorrĂªa AAS, Marconcini AC, Glenn J M, et al. (2012) Properties of thermoplastic starch from cassava bagasse and cassava starch and their blends with poly (lactic acid). Industrial Crops and Products, 37(1), 61–68. doi: 10.1016/j.indcrop.2011.11.036 
      6. 6.Garcia M, Pinotti A, Martino M, Zaritzky N (2009) Edible films and coatings for food applications. New York: Springer. (Chapter 6). 
        • 7.Muller C, Laurindo J, Yamashita F (2009) Effect of cellulose fibers addition on the mechanical properties and water vapor barrier of starch-based films. Food Hydrocolloids, 23, 1328–1333. doi: 10.1016/j.foodhyd.2008.09.002 
        • 8.Cyras VP, Manfredi LB, Ton-That MT, Vazquez A (2008) Physical and mechanical properties of thermoplastic starch/montmorillonite nanocomposite films. Carbohydrate Polymers, 73, 55–63. doi: 10.1016/j.carbpol.2007.11.014 
        • 9.Wilhelm H, Sierakowski M, Souza G, Wypych F (2003) Starch films reinforced with mineral clay. Carbohydrate Polymers, 52, 101–110. doi: 10.1016/s0144-8617(02)00239-4 
        • 10.Castillo L, Lopez O, Lopez C, Zaritzky N, GarcĂ­a MA, et al. (2013) Thermoplastic starch films reinforced with talc nanoparticles. Carbohydrate Polymers, 95, 664–674. doi: 10.1016/j.carbpol.2013.03.026 
        • 11.Belibi PC, Daou TJ, Ndjaka J-M, Michelin L, BrendiĂ© J, et al. (2013) Tensile and water barrier properties of cassava starch composite films reinforced by synthetic zeolite and beidellite. Journal of Food Engineering, 115, 339–346. doi: 10.1016/j.jfoodeng.2012.10.027 
        • 12.Xie FW, Pollet E, Halley PJ, Averous L (2013) Starch-based nano-biocomposites, Progress in Polymer Science, 38, 1590–1628. doi: 10.1016/j.progpolymsci.2013.05.002 
        • 13.Araujo-Farro PC, Podadera G, Sobral PJA, Menegalli FC (2010) Development of films based on quinoa (Chenopodium quinoa, Willdenow) starch. Carbohydrate Polymers, 81, 839–848. doi: 10.1016/j.carbpol.2010.03.051 
        • 14.Maran JP, Sivakumar V, Sridhar R, Thirugnanasambandham K (2013) Development of model for barrier and optical properties of tapioca starch based edible films. Carbohydrate Polymers, 92, 1335–1347. doi: 10.1016/j.carbpol.2012.09.069 
        • 15.Mehyar GF, Al-Ismail K, Han JH, Chee GW (2012) Characterization of edible coatings consisting of pea starch, whey protein isolate, and carnauba wax and their effects on oil rancidity and sensory properties of walnuts and pine nuts. Journal of Food Science, 77, 52–59. doi: 10.1111/j.1750-3841.2011.02559.x 
        • 16.De la Caba K, Peña C, Ciannamea EM, Stefani PM, Mondragon I, et al. (2012) Characterization of soybean protein concentrate-stearic acid/palmitic acid blend edible films. Journal of Applied Polymer Science, 124, 1796–1807. doi: 10.1002/app.35188 
        • 17.Garg S, Jana AK (2007) Studies on the properties and characteristics of starch–LDPE blend films using cross-linked, glycerol modified, cross-linked and glycerol modified starch. European Polymer Journal, 43(9), 3976–3987. doi: 10.1016/j.eurpolymj.2007.06.030 
        • 18.Mbey J, Hoppe S, Thomas F (2012) Cassava starch–kaolinite composite film. Effect of clay content and clay modification on film properties. Carbohydrate Polymers, 88, 213–222. doi: 10.1016/j.carbpol.2011.11.091 
        • 19.Shi AM, Wang LJ, Dong L, Adhikari B (2013) Characterization of starch films containing starch nanoparticles. Part 1: Physical and mechanical properties. Carbohydrate Polymers, 96, 593–601. doi: 10.1016/j.carbpol.2012.12.042 
        • 20.BodĂ®rlu R, Teac CA, Spiridon I, Tudorachi N (2012) Effects of chemical modification on the structure and mechanical properties of starch-based biofilms. Monatshefte fĂ¼r Chemie/Chemical Monthly, 143, 335–343. doi: 10.1007/s00706-011-0659-3 
        • 21.Muller CMO, Laurindo JB, Yamashita F (2011) Effect of nanoclay incorporation method on mechanical and water vapor barrier properties of starch-based film. Industrial Crops and Products 33, 605–610. doi: 10.1016/j.indcrop.2010.12.021 
        • 22.Wu M, Wang M, Ge MQ (2009) Investigation into the performance and mechanism of SiO2 nanoparticles and starch composite films. Journal of The Textile Institute, 100(3), 254–259. doi: 10.1080/00405000701757677 
        • 23.Chivrac F, Pollet E, Schmutz M, Averous L (2008) New approach to elaborate exfoliated starch-based nanobiocomposites. Biomacromolecules, 9, 896–900. doi: 10.1021/bm7012668 
        • 24.De Melo C, Salomao Garcia P, Grossmann MVE, Yamashita F, Dall’AntĂ´nia LH, et al. (2011) Properties of extruded xanthan-starch-clay nanocomposites films. Brazilian Archives of Biology and Technology, 54, 1223–1333. doi: 10.1590/s1516-89132011000600019 
        • 25.Mali S, Grossmann MVE (2002) Microstructural characterization of yam starch films. Carbohydrate Polymers, 50, 379–386. doi: 10.1016/s0144-8617(02)00058-9 
        • 26.Aila-SuĂ¡rez S, Palma-RodrĂ­guez HM, RodrĂ­guez-HernĂ¡ndez AI, HernĂ¡ndez-Uribe JP, Bello-PĂ©rez LA, et al. (2013) Characterization of films made with chayote tuber and potato starches blending with cellulose nanoparticles. Carbohydrate Polymers 98, 102–107. doi: 10.1016/j.carbpol.2013.05.022 
        • 27.Ungar T (2004) Microstructural parameters from X-ray diffraction peak broadening. Scripta Materialia, 51, 777–781. doi: 10.1016/j.scriptamat.2004.05.007 

        For further details log on website :

        http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0106727
        at No comments:
        Subscribe to: Posts (Atom)

        Advantages and Disadvantages of Fasting for Runners

        Author BY   ANDREA CESPEDES  Food is fuel, especially for serious runners who need a lot of energy. It may seem counterintuiti...