Donut-like hybrid latex comprising discrete thermoplastic lobe and thermosetting shell

Published Date

19 August 2016, Vol.98:252–262, doi:10.1016/j.polymer.2016.06.043

Title 

Donut-like hybrid latex comprising discrete thermoplastic lobe and thermosetting shell

• Author 

• Yeap-Hung Ng ^a
• Siok-Wei Tay ^b
• Liang Hong ^a,b,,

• aDepartment of Chemical & Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore
• bInstitute of Materials Research and Engineering, 2 Fusionopolis Way, Innovis, #08-03, Singapore, 138634, Singapore

Received 30 April 2016. Revised 15 June 2016. Accepted 16 June 2016. Available online 17 June 2016.

Highlights

• •
  OVPOSS-induced asymmetric growth leads to donut-like PS latex particles.
• •
  This hybrid latex comprises discrete thermoplastic lobe and thermosetting shell.
• •
  The spatially dual characteristics render anisotropic viscoelasticity inside latex.

Abstract

We achieve a donut-like polystyrene (PS) latex structure in a dispersion polymerization system where a low dose of octavinyl polyhedral oligomeric silsesquioxane (OVPOSS) is essential for inducing the asymmetric growth of latex particles. The evolution of donut shape is sensitive to polarity of dispersion medium, monomer conversion and substituted group of styrenic monomer. This asymmetric growth originates from the attaching of OVPOSS oligomers, i.e. nanoblocks (NB), to the surface of early PS particles, which launches a colony on each particle. Subsequent anchoring of OVPOSS surrounding the colony leads to a spread of NB, which concurrently impedes the growth of PS latex over the area they settle. While the uncovered patch continues expanding through propagation of PS radical chains, the region with a spreading of NB is consequently transformed to a concave thermosetting cap on a portion of individual PS particles. This anisotropic structure demonstrates unique viscoelastic characteristic shown by the latex films prepared.

Graphical abstract

Keywords

• Asymmetric growth
• Viscoelastic latex
• OVPOSS

---

Fig. 1.

 Table 1

Table 1.

Fig. 2.

Fig. 3.

Fig. 4.

Fig. 5.

Fig. 6.

Fig. 7.

Fig. 8.

 Table 2

Table 2.

Fig. 9.

Fig. 10.

Fig. 11.

• DOCX (10.2M)

• ∗ 
  Corresponding author. Department of Chemical & Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore.

For further details log on website :

http://www.sciencedirect.com/science/article/pii/S0032386116305183