Impact Strength Toughness

Impact strength toughness PVC, PP, PE ABS, ASA, SEBS, Block copolymer, SEBS, EPR, EPDM,... 

The properties of polymers vary considerably, making the match between polymer and application a sort through such characteristics as density, tensile and impact strength, toughness, melt index, creep, elasticity, heat and chemical stability, electrical properties, flammability, and price. 

Acrylonitrile-Butadiene-Styrene (ABS) Copolymers. This basic three-monomer system can be tailored to yield resins with a variety of properties. Acrylonitrile contributes heat resistance, high strength, and chemical resistance. Butadiene contributes impact strength, toughness, and retention of low-temperature properties. Styrene contributes gloss, processibility, and rigidity. ABS polymers are composed of discrete polybutadiene particles grafted with the styrene-acrylonitrile copolymer these are dispersed in the continuous matrix of the copolymer. 

PCO/PE Block copolymers with Ethylene or Propylene and norborene blocks low melt viscosity thus good processability, high elongation at break, impact strength, toughness, hardness, and modulus Epple and Brekner, 1994... 

The effects of minor proportions of PVC and PS in the polyolefins are quite dramatic. As little as 5% of PVC or PS in LDPE reduces the impact strength (toughness) of the latter by about 65%. This results from their presence as separate phases in the polyolefin matrix which leads to rapid crack propagation on impact. The effect of PP is very much less 10% of PP in LDPE reduced the energy absorbing capacity (toughness) of the matrix by only 1 % and 20% of PP reduced it by only 5%. The addition of block copolymers which act as compatibilisers or more correctly solid-phase dispersants (SPDs) for a second incompatible phase reduces the size of the heterogeneous domains and improves impact resistance. However, a considerable concentration ( 20%) of SPD is required, which unacceptably increases the cost in most cases. 

PURs are noted for their high impact strength, toughness and excellent resistance to abrasion. They bond well with reinforcements (one of the main applications of PURs is as adhesives) and offer very good resistance to chemicals. 

Ethylene-n-butyl acrylate (EBA) copolymers. EBA copolymers are also widely blended with olefin homopolymers to improve impact strength, toughness, heat sealability, and to promote adhesion. The polymerization process and resultant repeat imit of EBA are shown in Fig. 1.26. 

Bayer s Texin polyester and polyether TPU and TPU/polycarbon-ate (PC) elastomers were pioneer TPEs in early development of passenger car fronts and rear bumpers. PC imparts Izod impact strength toughness required for automotive exterior body panels. Extrusion applications include film/sheet, hose, tubing, profiles, and wire/cable covering. Hardness ranges from Shore A 70 to Shore D 75. Texin can be painted without a primer. 

An early, and widely used, commercial example of side-chain functionalities inducing interactions between polymer chains are ionomers, hydrocarbon macromolecules bearing, for example, carboxylic acid groups [e.g., poly(ethylene-co-methacrylic acid)], which are partially or fuUy neutralized with metal or quaternary ammonium ions. These ionomers are thermoplastic ionic polymers boasting unique physical properties such as enhanced impact strength, toughness, and thermal reversibility. They were developed and commercialized by DuPont, and have recently attracted attention due to their self-healing properties. ... 

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