| abstract |
A novel thermoplastic elastomer (TPE) which comprises (i) polymeric A blocks in which there are side chains comprising crystallizable moieties having a melting point Tq, and (ii) at least one amorphous polymeric B block having a glass transition point, Tgs, which is less than (Tq - 10)°C. The relative proportions and molecular weights of the A and B blocks can be adjusted so as to produce desired physical properties with comparatively little change in Tq, which depends chiefly upon the nature of the crystallizable moieties, which may be for example n-alkyl groups containing 12 to 50 carbon atoms. The novel TPE's show a sharply reduced viscosity in the region of Tq, and can be melt-processed at temperatures close to Tq. The novel TPE's are useful in the form of compositions, shaped articles and assemblies which comprise one of the novel TPE's and a second component which is mixed with, or surrounded by, or surrounds or otherwise provides a substrate for, the TPE. Preferred second components are explosives and other energetic materials, pharmaceuticals, seeds, perfumes, deodorizers, pest control agents, herbicides, insecticides, fungicides, biologically active materials, agrichemicals, and disinfectants. Second components can be released from such a composition or shaped article by a natural increase in the ambient temperature or by heating the composition or article to a temperature at least equal to Tq by means of heat which is (i) generated artificially or (ii) generated by a mammalian body and/or (iii) is conveyed artificially to the composition, article or assembly. |