Polyisobutylene/polystyrene

Puskas, J.E. et al. Synthesis and characterization of novel dendritic (arborescent) polyisobutylene-polystyrene thermoplastic elastomers, J. Polym. Set A, 43, 1811, 2005. 

Puskas, J.E., Antony, P., Pray, M., and Altstadt, V. Effect of hard and soft segment composition on the mechanical properties of polyisobutylene-polystyrene thermoplastic elastomeric block copolymers, Eur. Polym. J., 39, 2041-2049, 2003. 

St. Lawrence, S., Shinozaki, D.M., Puskas, J.E., Gerchcovich, M., and Myler, U. Micro-mechanical testing of polyisobutylene-polystyrene block-type thermoplastic elastomers. Rubber Chem. TechnoL, 74, 601-613, 2001. 

Antony, P., Puskas, J.E., and Kontopoulou, M. The Rheological and Mechanical Properties of Blends Based on Polystyrene-Polyisobutylene-Polystyrene Triblock Copolymer and Polystyrene. Proceedings of MODEST, International Symposium on Polymer Modification, Degradation and Stabilization, Budapest, Hungary, 2002. 

Puskas, J.E., Pattern, W.E., Wetmore, P.M., and Krukonis, A. Synthesis and characterization of novel six-arm star polyisobutylene-polystyrene block copolymers. Rubber Chem. TechnoL, 72, 559-568, 1999. Puskas, J.E., Wetmore, P.M., and Krukonis, A. Supercritical fluid fractionation of polyisobutylene-polystyrene block copolymers, Polym. Prepr., 40, 1037-1038, 1999. 

Kwon, Y., Antony, P., Paulo, C., and Puskas, J.E. Arborescent polyisobutylene-polystyrene block copolymers—a new class of thermoplastic elastomers, Polym. Prepr., 43, 266-267, 2002. 

El Fray, M., Puskas, J.E., Tomkins, M., and Altstadt, V. Evaluation of the Eatigue Properties of a Novel Polyisobutylene-Polystyrene Thermoplastic Elastomer in Comparison with other Rubbery Biomaterials. Paper 76, ACS Rubber Division, 166th Technical Meeting, October 5-8, Columbus, OH, 2004. Puskas, J.E. and Chen, Y. Novel Thermoplastic Elastomers for Biomedical Applications. Paper 40, ACS Rubber Division, 163nd Technical Meeting, April 28-30, San Erancisco, CA, 2003. 

Cationic Polyethylene Polyisobutylene Polystyrene Vinyl esters... 

These tests, however, do not identify certain chemically very inert plastics such as polyethylene, polypropylene, polyisobutylene, polystyrene, polymethyl methacrylate, polyacrylates, polyethylene terephthalate, natural rubber, butadiene rubber, polyisoprene, and silicones. Their identification requires specific individual reactions, described in Chapter 6. 

The discovery of living cationic polymerization has provided methods and technology for the synthesis of useful block copolymers, especially those based on elastomeric polyisobutylene (Kennedy and Puskas, 2004). It is noteworthy that isobutylene can only be polymerized by a cationic mechanism. One of the most useful thermoplastic elastomers prepared by cationic polymerization is the polystyrene-f -polyisobutylene-(>-polystyrene (SIBS) triblock copolymer. This polymer imbibed with anti-inflammatory dmgs was one of the first polymers used to coat metal stents as a treatment for blocked arteries (Sipos et al., 2005). The SIBS polymers possess an oxidatively stable, elastomeric polyisobutylene center block and exhibit the critical enabling properties for this application including processing, vascular compatibility, and biostability (Faust, 2012). As illustrated below, SIBS polymers can be prepared by sequential monomer addition using a difunctional initiator with titanium tetrachloride in a mixed solvent (methylene chloride/methylcyclohexane) at low temperature (-70 to -90°C) in the presence of a proton trap (2,6-dt-f-butylpyridine). To prevent formation of coupled products formed by intermolecular alkylation, the polymerization is terminated prior to complete consumption of styrene. These SIBS polymers exhibit tensile properties essentially the same as those of... 

Data on migration of plasticizers of various chemical structures from plasticized PVC films into non-plasticized PVC, polyisobutylene, polystyrene, PMMA, and other polymers can be found elsewhere. These results show the influence of the natures of plasticizer and polymer on plasticizer migration during contact of the two materials. Data on the equihbrium content of plasticizers in contact with polymer products containing plasticizer... 

The Henry s law constant for a given polymer can be correlated with the e/ k factor (see Table 5-4). Such correlations are shown in Figs. 5-12 and 5-13. A more generalized correlation is shown in Fig. 5-14, where the Henry s law constant is correlated with the gas critical temperature for thermally softened polymers (polyisobutylene, polystyrene, and polymethyl methacrylate). Figure 5-14 offers the possibility of estimating a Henry s law constant for a polymer for which there are no data. 

Estimate the Henry s law constants for carbon monoxide, oxygen, and ethane at 188°C in polyethylene, polypropylene, polyisobutylene, polystyrene, and polymethyl methacrylate. 

Fig. 8. Reduced surface tension versus reduced temperature of polymers. Solid line is Poser Sanchez theory with ic = 0.55 O branched polyethylene linear polyethylene polyisobutylene polystyrene A poly(vinylacetate) A poly(dimethyl siloxane). From Ref. 21.

Kwon Y, Antony P, Paulo C and Puskas J E (2002) Arborescent polyisobutylene-polystyrene block copolymers - A new class of thermoplastic elastomers, Polym Prepr ACS 43 266-267. 

S. E. Keinath We didn t do any DSC work on the polyisobutylene/polystyrene blends, that was strictly DMA work. Regarding the variation of particle size in the DSC, yes, we do see an effect. We haven t looked at any silicone oil encapsulation of samples in the DSC. That would alleviate some of the surface contact phenomena going on with some of the particles, which is a real effect in DSC. Frequently, you get better reproducibility in the Tg and Tn temperatures if you look at a second heating of a sample of polystyrene. In a second heat, you don t have to worry about the melt flow contact of the sample to the DSC pan itself. 

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