Vulcanizate tensile molecular weight

Increase in the molecular weight of the polychloroprene, increasing viscosity and tensile strength of vulcanizates. 

A VDF unit also follows FIFP m the structurally much more complex terpo-lymers [30] Dipolymers contain 60 wt % VDF (66% F) and terpolymers contain 33-50 wt % VDF (66-69 5% F) and generally less than 28 wt % TFE Molecular weights range from 1 5 x 10 to 10 Their respective continuous service temperature ranges are -18 to 210 °C and -12 to 230 °C Dipolymer vulcanizates retam over 50% of their tensile strength for more than 1 year at 200 °C or for 2 months at 260 C... 

Butyl ruhher vulcanizates have tensile strengths up to 2,000 psi, and are characterized hy low permeahility to air and a high resistance to many chemicals and to oxidation. These properties make it a suitable rubber for the production of tire inner tubes and inner liners of tubeless tires. The major use of butyl rubber is for inner tubes. Other uses include wire and cable insulation, steam hoses, mechanical goods, and adhesives. Chlorinated butyl is a low molecular weight polymer used as an adhesive and a sealant. 

Among the main molecular structural variables in EPDMs that are stipulated by catalyst systems and that affect the vulcanizate tensile properties we may mention molecular weight (MW) and MWD, degree of unsaturation (LG=C 1) and its distribution in the polymer, composition (C S) and monomer sequence length distribution along molecular chains, and long-chain branching if present. Effect of... 

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