Structure‐property relationships in elastomer‐modified terpolymer systems

Abstract

synopsisA number of terpolymers, incorporating as the elastomer phase polybutadiene, polyisoprene, poly-2,3-dimethylbutadiene, poly (butadiene-co-styrene), and poly (butadieneco-2-methyl-kinylpyridine), were studied. Matrices were composed of poly(styreneco-acrylonitrile) (SAN), poly(a-methylstyrene-co-acrylonitrile), and poly(styrene-coacenaphthylene). At constant elastomer content and elastomer molecular weight in systems employing a SAN matrix, Izod impact resistance was found to vary inversely with rising elastomer-glass transition temperature. In systems of various matrix composition, using a polybutadiene elastomer, heat deflection temperatures were found to vary directly and impact resistance inversely with rising matrix-glass transition temperature. In acrylonitrile-butadene-styrene (ABS), systems of constant matrix composition and elastomer content, varying the elastomer molecular weight, from 0.6 to 2.6 x 106 resulted in increasing the Izod impact resistance from 0.67 to 12.8 fblb/in. of notch.

Study on polyethylene glycol/polydimethylsiloxane mixing soft-segment waterborne polyurethane from different mixing processes

“…In general, polydimethylsiloxane (PDMS) has the following characteristics: (1) rather low glass‐transition temperature ( T g ; approximately −123°C)3, 4; (2) excellent heat stability, oxidation resistance, is inert to high or low temperatures, and is weatherproof (this is attributed to its possessing very strong SiO bonding energy at about 108 kcal/mol)5; (3) great molecular flexibility (attributed to its low intermolecular attraction)4; (4) high impact resistance6, 7; (5) excellent resilience8; (6) good electric insulation; (7) high oxygen permeability9; (8) nontoxicity10; and (9) low surface energy (that can easily transfer around on the surface of the polymer and provide good hydrophobicity) 11–14. The introduction of the PDMS component into PU can be expected to improve the PU's integral and surface properties.…”

Morphology Considerations in Heterogeneous Latexes for Impact Polymers

“…A major limitation of all the property studies of latex impact polymers conducted to date [20,21,[32][33][34][35][36][37] is that they have not reported adequately on the detailed particle morphology or, in some cases, even on particle size of the base rubber latex. In order to gain a thorough understanding and a complete correlation of the effect of reaction variables on product properties all of the pertinent variables must be controlled and their influences assessed.…”

Chain‐End and Chain‐Internal Crosslinking in “Latent Reactive” Silicon Elastomers

“…[1][2][3][4][5][6] The addition of silica-based fillers helps, improving elongation and the overall mechanical properties of such materials. [50][51][52][53][54] Additional enhancements of these materials (PDMS) can be realized by the covalent incorporation of carbon segments either via block or graft architectures using traditional condensation or chain-addition polymerizations. Numerous examples of these hybrid materials exist, such as PDMS-block-polysulfone, [55] PDMS-blockpoly(methyl methacrylate), [56] PDMS-block-polyamide-6, [57] PDMS-block-poly(a-methylstyrene), [58] PDMSblock-(bisphenol A polycarbonate), [59] PDMS-block-polystyrene, [60] poly(vinyl alcohol)-graft-PDMS, [61] and segmented polyurethane-graft-PDMS [62] were synthesized and analyzed by different research groups.…”