Effect of the addition of acrylonitrile/ethylene–propylene–diene monomer (EPDM)/styrene graft copolymer on the morphology–properties relationships in poly(styrene‐co‐acrylonitrile)/EPDM rubber blends

Abstract

ABSTRACT:Blends of poly(styrene-co-acylonitrile) (SAN) with ethylene-propylene-diene monomer (EPDM) rubber were investigated. An improved toughness-stiffness balance of the SAN/EPDM blend was obtained when an appropriate amount of acrylonitrile-EPDM-styrene (AES) graft copolymer was added, prepared by grafting EPDM with styrene-acrylonitrile copolymer, and mixed thoroughly with both of the two components of the blend. Morphological observations indicated a finer dispersion of the EPDM particles in the SAN/EPDM/AES blends, and particle size distribution became narrower with increasing amounts of AES. Meanwhile, it was found that the SAN/ EPDM blend having a ratio of 82.5/17.5 by weight was more effective in increasing the impact strength than that of the 90/10 blend. From dynamic mechanic analysis of the blends, the glass-transition temperature of the EPDM-rich phase increased from Ϫ53.9 to Ϫ46.2°C, even Ϫ32.0°C, for the ratio of 82.5/17.5 blend of SAN/EPDM, whereas that of the SANrich phase decreased from 109.2 to 108.6 and 107.5°C with the additions of 6 and 10% AES copolymer contents, respectively. It was confirmed that AES graft copolymer is an efficient compatibilizer for SAN/EPDM blend. The compatibilizer plays an important role in connecting two phases and improving the stress transfer in the blends. Certain morphological features such as thin filament connecting and even networking of the dispersed rubber phase may contribute to the overall ductility of the high impact strength of the studied blends. Moreover, its potential to induce a brittle-ductile transition of the glassy SAN matrix is considered to explain the toughening mechanism.

Phase morphology and thermomechanical analysis of poly(styrene‐co‐acrylonitrile)/ethylene–propylene–diene monomer blends: Uncompatibilized and reactively compatibilized blends with two mixing sequences

“…To improve this sometimes undesirable situation caused by unstable craze deformation, it is often modified with rubber particles 14–18. Often, however, the immiscibility and incompatibility of the rubber with SAN produce poor physical properties in the blend 19–24. A compatibilization strategy is then required to improve the physical properties.…”

Preparation of PBAS core‐shell structured polymer by seeded emulsion polymerization and investigation in AS resin toughness

“…The characteristic peaks of AS [Fig. 4(a)] appeared at 2239 cm −1 for the CN stretching vibration, and at 760 cm −1 and 702 cm −1 for the mono‐substituted benzyl ring characteristic vibrations 8. Both the spectra of the soluble [Fig.…”

“…As ABS resin contains double bonds on the backbone, it is easy to cause ageing reactions, especially for outdoor use of these materials. The substitution of the ethylene‐propylene‐diene terpolymer (EPDM) for poly(butadiene) by the method of solution graft copolymerization has been widely investigated to overcome this problem 4–8. Even so, solution copolymerization will suffer lower copolymerization rate and monomer conversion.…”

“…FTIR, NMR, DMA, TEM, and SEM measurements were used to evaluate the relationships between structures and properties of AS/PBAS blends and investigate the phase structure, toughing mechanism of AS/PBAS blends. This work might be expected to improve the thermal stability of ABS and the processing procedure of acrylonitrile‐EPDM‐styrene (AES) copolymer compatibilizing with AS/EPDM blends,8 for it is known that polyacrylics have outstanding resistance to heat, light, oxygen, and ozone because of its nonconjugated diene component. On the basis of the results, we show the importance of toughening these brittle/rubber polymer systems to have a practical use of this material in industry.…”

Morphology and thermal behaviour of SAN/EPDM blends

“…The second method, often called reactive extrusion or reactive compatibilization, allows us to generate the compatibilizer in situ at the interfaces directly during blending [4,5]. System called acrylonitrile-ethylene/propylene/diene elastomer-styrene (AES), which is formed by EPDM rubber dispersed into a glassy matrix of a SAN copolymer, containing also SAN molecules grafted onto the EPDM rubber (EPDM-g-SAN) which act as compatibilizing agents between the two immiscible components [6,7]. Generally, the rubbery particles are grafted by a brittle polymer which is the same as the matrix.…”