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Application of TGA and DTA to Polymeric Systems (Neat Polymeric Systems)
Published in Jose James, K.P. Pramoda, Sabu Thomas, Polymers and Multicomponent Polymeric Systems, 2019
Dilipkumar Pal, Vinod Kumar Gurjar
Thermal stability measurements have been carried out on numerous other polymers including polyethylene ethylene vinyl–alcohol copolymer (Matsuda et al. 2003), polyaniline (Dan and Sengupta 2004), trans-stilbene–N-substituted maleimides (Orzaev et al. 1996), cellulose (Dollimore and Holt 1973), polystyrene (Basch and Lewin 1973), ethylene–styrene copolymers (Judd and Norris 1973), vinyl chloride–acrylonitrile copolymers (Joesten and Johnston 1974), polyethylene terephthalate (Franck et al. 1995), amine-based polybenzo-oxazines (Hemvichian and Ishida 2002), polyesters such as polyisopropylene carboxylate (Hodd and Holmes-Walker 1973), polyglycollate (Sutton and Tighe 1973) Nylon 6 (Varma and Ravisankar 1973, Lehrle et al. 2000), (Chattopadhyay and Webster 2009), ethylene–vinyl acetate copolymer (Allen et al. 2000), polyvinyl chloride (Liebman et al. 1978), acrylamide–acrylate copolymers and polyacrylic anhydride (Dassanayake and Philips 1984), polyamides (Turk et al.1999), polyester hydrazides (Capatini et al. 2001), polytetrahydrofuran (Kojima et al. 2003), polyurethanes polymethacrylates (Ilter et al. 2002), poly-p-methyl styrene (Boinon et al. 1988), styrene–isoprene copolymer (Böker et al. 2002), polyether sulfone (Li et al. 2003), acrylonitrile–butadiene–styrene compositions (Yang et al. 2004), fluorinated polyimides (Turk et al. 1999), and PMMAs (Omastovšá et al. 1998).
Polyols for Polyurethane Production
Published in Eric J. Goethals, Telechelic Polymers: Synthesis and Applications, 2018
David J. Sparrow, David Thorpe
Polytetrahydrofuran or polytetramethylene glycol ether is produced by the polymerization of tetrahydrofuran.18 The five-membered ring of tetrahydrofuran is more stable than the three-membered ring of ethylene or propylene oxide, and as a consequence, it will not polymerize under the influence of alkali catalysts. However, acid catalysts, such as fluorosulfonic acid, are effective and used in the manufacture of polytetramethylene glycol ether. Using fluorosulfonic acid at a level of approximately 10% by weight of the tetrahydrofuran, the polymerization proceeds smoothly at temperatures around 35°C.253 At the end of the reaction hydrolysis of the product is required to convert the end-groups to hydroxyl groups. ()
Inelasticity of hard-phase reinforced elastomers: A study of copolyurethanes with varying hard and soft segments
Published in Per-Erik Austrell, Leif Kari, Constitutive Models for Rubber IV, 2017
P.C. Buckley, C. Prisacariu, A.A. Caraculacu, C.M. Martin
A family of thermoplastic polyurethanes was synthesised by the authors in the Romanian laboratory. They were all three-component systems combined in stoichiometric proportions, and consisting of: (1) a diisocyanate (DI) generating a hard segment HS (MDI or DBDI); (2) a soft segment macrodiol MD – poly (ethylene adipate) PEA, polytetrahydrofuran PTHF, or poly(butylene adipate) PBA; and (3) a small molecule diol as chain extender CE – anhydrous ethylene glycol EG, diethylene glycol DEG, or butylene glycol BG. The macrodiols were all of molar mass Mw = 2000 ± 50 g mol–1. The three components were always mixed in the proportions HS:CE:MD 4:3:1, giving hard segment mass fractions in the region of 30%, and isocyanic index I 100. The synthesis procedure followed was the pre-polymer route described previously by Prisacariu et al. (2003). The HS and MD components were reacted together with vigorous mixing under vacuum at 100°C, to give prepolymer terminated by HS. This was then thoroughly mixed with the CE at 90°C, and cast into closed sheet moulds for curing at 110°C for 24 hours. The final result was polymer with Mw in the range 60–120 kg mol−1, in the form of sheets with thickness in the range 0.3–0.6 mm. The sheets were stored at room temperature for at least one month before testing. They were labeled Pu1– Pu14 according to their combination of HS, MD and CE, as indicated in the table below. It should be noted that the stoichiometric proportions used in these polymers (I 100) means they are thermoplastic: they do not have the potential for further reaction with ambient humidity to produce chain lengthening and allophanate cross-links, seen in similar polymers but with excess isocyanate groups (e.g. I 110, see Prisacariu et al. 2003).
Employing adhesion technology to bond natural rubber faceblank and polyurethane elastomer flexible lens for gasmask
Published in The Journal of Adhesion, 2020
DeYin Wang, ShiPeng Wen, XiaoYin Li, XiLe HuangFu, Lei Li
The flexible lens used in this research was a type of non-yellowing PUE followed a two-step, pre-polymer synthesis method from isophorone diisocyanate (IPDI), polytetrahydrofuran glycol (PTMG), mixed chain extenders trimethylolpropane (TMP) and 1,4-butanediol (BDO). Physical properties of the PUE flexible lens substrates were shown in Table 1.