Latex derived blends of poly(vinyl acetate) and natural rubber: thermal and mechanical properties
- 287 Downloads
Poly(vinyl acetate) (PVAc) and natural rubber blends (NR) were prepared by low shear blending of the corresponding lattices. Thin films were cast using a doctor blade technique. SEM and DMA confirmed the essential immiscibility of the two polymers. Even when the poly(vinyl acetate) forms the matrix phase, it still contains domains encapsulated by a rubber phase where particles that resemble the original latex are visible. This incomplete droplet coalescence of the poly(vinyl acetate) is attributed to the fact that the rubber latex droplets were an order of magnitude smaller than the poly(vinyl acetate) latex droplets. Tensile testing revealed a nonlinear dependence of tensile strength and elongation on blend composition. Surprisingly good tensile yield strengths were obtained at intermediate to high PVAc contents. Thermogravimetric analysis of degradation in air and nitrogen atmospheres indicated independent degradation of the parent polymers.
KeywordsNatural Rubber Dynamic Mechanical Analysis PVAc Vinyl Acetate Emulsion Droplet
Financial support for this research from the Institutional Research Development Programme (IRDP) of the National Research Foundation (NRF), the University of the Free State and the University of Pretoria is gratefully acknowledged.
- 1.Paul DR, Sperling LH (1986) Adv Chem Ser 211:1Google Scholar
- 2.Gesner BD (1967) Polym Prepr (Am Chem Soc Div Polym Chem) 8:1482Google Scholar
- 3.Bergen RL Jr (1967) Polym Prepr (Am Chem Soc Div Polym Chem) 8:1473Google Scholar
- 4.Utracki LA, Weiss RA (1989) Multiphase Polymers, ACS Symp Ser 195:1Google Scholar
- 5.Dyson RW (1990) Engineering polymers. Chapman and Hall, New York, p 20Google Scholar
- 8.Brydson JA (1975) Plastics materials, 3rd edn. Newnes-Butterworths, London, p 317Google Scholar
- 16.Winnik MA, Feng J (1996) J Coat Technol 68:39Google Scholar
- 22.Pizzi A (1983) Wood adhesives—chemistry and technology. Marcel Dekker, New York, p 328Google Scholar
- 24.Brandrup J, Immergut EH (1989) Polymer handbook, 3rd edn. Wiley, New YorkGoogle Scholar