The role of the tackifier in a pressure sensitive adhesive tape was investigated.For this purpose, amodel pressure sensitive adhesive was prepared using the acrylic block copolymer consisting of poly(methylmcthacrylate) and poly(butylacrylate) as a base polymer and a tackifier.The poly (butylacrylate) oligomer was also used as a diluent to compare the effect on the adhesion properties.Tack was measured using a rolling tack tester in wide temperature and rolling rate ranges, and the mastercurve was made in accordance with the time-temperature superposition law.The tack increased andthe failure mode varied from cohesive failure to interfacial failure with an increase in the test rate.The tack was higher in the tackifier added system than in the oligomer added system. From a dynamic mechanical analysis,the modulus of elasticity at high temperature decreased by the addition ofboth tackifier and oligomer, however, the glass transition temperature of poly (butylacrylate) andthe modulus of elasticity at low temperature increased only by the addition of tackifier.The dynamicviscoelastic properties were measured in wide temperature and frequency ranges, and the master curve was also made. The viscoclastic properties varied in the order of viscosity, rubbery and glassy withan increase in the deformation rate.It was clarified that the tack value and the failure mode werestrongly dependent upon the viscoclastic properties of adhesive. And both tackifier and oligomerimproves the mobility of the base polymer, whereas, only the tackifier increases the cohesive strengthof the base polymer.

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Poly(e-caprolactone) (PCL) fibers were degraded by lipoprotein lipase (LPL) modified with copoly(L-glutamicacid/L-alanine) (EA) invitro.The degradation of PCL fibers by EA-modified LPL (EA-LPL) was assessed by the weightloss, mechanical properties loss such as tensile strength and ultimate elongation decrease.The results were compared with those obtained with free LPL.The degradation kinetics on the weight loss of PCL fibers suggested that the degradation of PCL fibers gradually proceeded from the surface of fibers into their core.The weight loss of PCL fibers in the course of EA-LPL digestion took place almost in parallel with the strength loss of PCL fibers, while thestrength loss took place at a higher rate than the weight loss of PCL fibers in the course of free LPLdigestion.The degradation of PCL fibers was found to depend on the draw ratio and crystallinity ofPCL fibers.

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