Polycarbonate diols

Polyester and polyether diols are used with MDI in the manufacture of thermoplastic polyurethane elastomers (TPU). The polyester diols are obtained from adipic acid and diols, such as ethylene glycol, 1,4-butanediol, or 1,6-hexanediol. The preferred molecular weights are 1,000 to 2,000, and low acid numbers are essential to ensure optimal hydrolytic stabihty. Also, caprolactone-derived diols and polycarbonate diols are used. Polyether diols are... 

Ring opening polymerisation of cyclic carbonates, initiated by glycols, leads to polycarbonate diols (reaction 8.5). 

The polyester polyurethanes based on polycarbonate diols and the intrinsic hydrolysis resistance of these special kind of polyurethanes were discussed before (Section 8.1). 

Yu et al. reported that poly[lactic acid]-block-[polycarbonate diol] [PLA-PCD] copolymers were synthesized using a two-step process with polycondensation and chain extension reactions [shown in Fig. 23.5]. The PLA-PCD copolymers obtained could crystallize, and the crystallinity decreased with chain-extension reaction. The products exhibited superior mechanical properties with elongation at break above 230%, which was much higher than that of PLA chain-extended products. The products had a good potential for packaging applications [20]. 

Poly (1,4-phenylene sulfide) resin. See Polyphenylene sulFrde resin Poly [(phenyl glycidyl ether)-co-farmaldeh e. See Epoxy-novolac Polyphenylmethyl siloxane. See Phenyl methicone Phenyl trimethicone Polyphosphoric acid, ammonium salt. SeeAmmonium polyphosphate Poly (polytetrahydrofuran carbonate) diol. See Polyether-polycarbonate diol... 

Poiypiasdone iNF-10, Poiypiasdone XL, Poiypiasdone XL-10. See Crospovidone Poiypiastoi 10. See Pentaerythrityl stearate Poiypiastoi 23. See Zinc 2-ethylhexanoate Poiypiate 90, Poiypiate 852, Poiypiate P, Poiypiate P01. See Kao I i n PoiypoilQ. See Polypropylene Poly (polytetrahydrofuran carbonate) diol. See Polyether-polycarbonate diol Polypropene. See Polypropylene Polypropylene CAS 9003-07-0... 

Poly (tetramethylene terephthalate). See Polybutylene terephthalate Polytex 10. See Stearamide DIBA-stearate Poly-Tex 950. See Hydroxypropyl methacrylate Poly-Tex 975, Poly-Tex 9008. See Acrylic resin Polythene. See Polyethylene PolyTHF 25a, PolyTHF 650. See Polytetramethylene ether glycol PolyTHF 100a, PolyTHF 2000. See Polyether-polycarbonate diol... 

Tetrahydro-2-furancarbinol. See Tetrahydrofurfuryl alcohol Tetrahydrofuran, compd. with carbonic acid. See Polyether-polycarbonate diol Tetrahydrofuran homopolymer. See Polytetramethylene ether glycol Tetrahydro-2-furanmethanol. See Tetrahydrofurfuryl alcohol Tetrahydro-2-furanmethanol acetate. See Tetrahydrofurfuryl acetate Tetrahydro-2-furanone. See Butyrolactone Tetrahydrofurfuryl acetate CAS 637-64-9 EINECS/ELINCS 211-296-8 FEMA 3055... 

Available as a dimethyl acetamide solution, this segmented, aromatic, polycarbonate-based TPE polyurethane was designed to mimic Ethicon Corporation s Biomer. The polymer is made from the addition of diphenylmethane 4,4 -diisocyanate to a polycarbonate diol followed by addition of a mixture of chain extenders and a molecular weight regulator. The polymer is believed to be resistant to environmental stress cracking such as that experienced by other polyurethanes coated onto pacemaker leads (Tables 4.4, 4.12, and 4.13). 

A polycarbonate TPE polyurethane that claims biostability is achieved through its replacement of virtually all ether or ester linkages with carbonate groups. The soft segment is composed of a polycarbonate diol formed by the condensation reaction of 1,6-hexanediol with ethylene carbonate. The polycarbonate diol is converted to a high molecular weight polyurethane by the reaction with 1,4-methylene bisphenyl diisocyanate (MDI) and 1,4-butanediol. It is reported to be resistant to environmental stress cracking as experienced with insulation on pacemaker lead wires. The polymer can be extruded, injection molded or compression-molded, and can be bonded with conventional urethane adhesives and solvents (Tables 4.4, 4.12, 4.13, and 4.14). 

Urethane Single Tg II was based on 3,3 -diphenylmethane diisocyanate and aliphatic polycarbonate diols and/or polytetramethylene glycol Fambri et al. (1997)... 

SMPU containing polycarbonate segments were synthesized by the prepolymer method of an aliphatic polycarbonate diol. The macrodiol was synthesized by copolymerization of ethylene oxide in the presence of CO2 catalyzed by a polymer supported bimetallic catalyst [60]. In these polycarbonate urethanes Ttrans = 7g and was around 5 C. Another example with higher Ttrans are segmented polyesterurethanes based on a copolymer of L-lactide and e-caprolactone, providing the switching domains as well as the polyurethane from butanediol and 2,4-toluene diisocyanate [52]. Tsw could be adjusted between 28 and 53 °C. Rr was determined between 93 and 100%. 

Polyurethanes, particularly those based on polyesters, are well known for their oil and grease resistance however, they are susceptible to attack by moisture. The structure of the backbone has a profound influence on the hydrolytic stability. The more hydrophobic the backbone, the greater the resistance of the polyurethane towards hydrolysis. Thus, polyether polyurethanes are inherently more stable to hydrolysis than polyester-based materials, and HTPBD-based polyurethanes are even more stable than the polyether materials. Polyurethanes prepared from polycarbonate diols have also been reported to display very good hydrolytic stability. " ... 

Polyadipates, polycarbonate diols, and polyethers based on long-chain diols as components of the TPU molecule result in higher hydrolysis resistance. Esters with hydrophobic diol and an acid with low dissociation constant are especially well protected against the influence of hydrolysis. Long-chain diols are thus more hydrolysis resistant than short-chain diols [86]. 

The thermoset PC-related bioelastomers from multi-carboxylic acids were synthesized by a melt polycondensation. The multifunctional carboxylic acids referred to tricarballylic acid (Yt) and trimesic acid (Y), and polycarbonate diols presented the molecular weights of 1000 g moC and 2000 g mol (named as PCDiooo and PCD2ooo)- The molecular structures of Yt, Y and the polycarbonate... 

Scheme 8.16 Molecular structures of tricarballylic acid, trimesic acid and polycarbonate diol used in the preparation of thermoset polycarbonate related bioelastomers.

PUMAs were obtained by two-step bulk polymerization, using a polycarbonate diol (PHCD) as macroglycol, an aliphatic diisomaleic acid butane diol as chain extenders. The reagents were used in the stoichiometric ratio PHCD diisocyanate chain extender = 1 2 1. Dibutyl-tin-dilaurate or staimous octanoate were used as catalysts. All of them were purified from residual catalyst, and solvent-cast from DMA solutions. 

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