Graft copolymers reinforced thermoplastic

Biofiber Graft Copolymers Reinforced Thermoplastic Composites I 271... 

Graft Copolymers of EPDM Elastomers as Reinforcing Agents for Brittle Thermoplastic Materials... 

With both the PEA/P(S-co-MMA) and PB/PS IPN s, an important variable is the ratio of elastomer to plastic in the final material. When the plastic component predominates, a type of impact-resistant plastic results. In this manner the PB/PS IPN s are analogous to the impact-resistant graft copolymers. When the elastomer component predominates, a self-reinforced elastomer results, the behavior resembling that of the ABA-type block copolymers (thermoplastic elastomers) described in Section 4.4. When the overall compositions of both the PB/PS and the PEA/P(S-co-MMA) series are close to 50/50, the materials behave like leathers. 

Volume 1 of this book is comprised of 25 chapters, and discusses the different types of natural rubber based blends and IPNs. The first seven chapters discuss the general aspects of natural rubber blends like their miscibility, manufacturing methods, production and morphology development. The next ten chapters describe exclusively the properties of natural rubber blends with different polymers like thermoplastic, acrylic plastic, block or graft copolymers, etc. Chapter 18 deals entirely with clay reinforcement in natural rubber blends. Chapters 19 to 23 explain the major techniques used for characterizing various natural rubber based blends. The final two chapters give a brief explanation of life cycle analysis and the application of natural rubber based blends and IPNs. 

In order to develop composites with better mechanical properties and environmental performance, it becomes necessary to increase the hydrophobicity of the biofibers and to improve the interface between matrix and biofibers. Graft copolymerization of biofibers is one of the best methods to attain these improvements. As of now, only few studies have reported the use of biofiber graft copolymers as reinforcing material in the preparation of composites [33], Mechanical properties of thermoplastic composites reinforced with acrylate-gro/led henequen cellulose fibers were studied. It has been found that best results could be obtained with poly(methyl methacrylate) (PMMA)-grafted cellulose fibers because of better fiber-matrix adhesion. The modulus of poly(vinyl chloride) (PVC) composites is increased when grafted or ungrafted cellulose are used as reinforcement but the composites with... 

The impact strength of brittle thermoplastic materials is generally improved by adding small amounts of rubber, either pure or modified by grafting with the monomer or monomers constituting the matrix to be reinforced (1, 2, 3, 4, 5). As a rule, modification is achieved by monomer polymerization in the presence of the reinforcing elastomer, which is usually a butadiene polymer or copolymer (6, 7). 

EPR random copolymers are inherently thermoplastic and rubbery in nature but to give them useful levels of strength, creep resistance, heat resistance, and solvent resistance, they are commonly blended, or block or graft copolymerized, with crystalline polyolefins, particularly polypropylene, which on cooling separate as crystalline domains and act as thermoplastic crosslinks and reinforcing fillers. ... 

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