Acyclic polymers containing a large number of isoprene subunits, usually unsaturated.
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However, NR alone does not exhibit sufficient adhesive tack, which can be defined as the ability to adhere to other materials with dissimilar compositions [1], Therefore, tackifying resins (e.g., rosin derivatives, aliphatic or aromatic hydrocarbon resins, and polyterpenes) are typically used to improve the surface adhesion of NR to other materials [2, 3].
Depending on the number of blocks, they can be classified as monoterpenes (C10), sesquiterpenes (C15), diterpenes (C20), triterpenes (C30), tetraterpenes (C40), and polyterpenes [21].
They are classified as hemiterpenes (C5), monoterpenes (C10), sesquiterpenes (C15), diterpenes (C20), sesterpenes (C25), triterpenes (C30), tetraterpenes (C40), and polyterpenes (>C40).
The adhesive composition comprises an amorphous polyalpha-olefin and a tackifier selected from at least one of the group consisting of: petroleum distillates, rosin, rosin esters, and polyterpenes. The bonded structure has a dynamic peel strength between about 150 and about 1000 grams per 25 millimeters.
Absorptions at 1170 and 1145 [cm.sup.-1] typical of isopropyl groups derived from lignin decomposition are more visible in semicoking liquids, while mono-, sesqui-, and polyterpenes manifest themselves at 2800-3000 and 800-840 [cm.sup.-1] conspicuously in bark- and needle-derived liquids.
Rosin derivatives, polyterpenes and petroleum resins can be used for pressure-sensitive adhesives.