Polyurethanes polycaprolactone-based

Busfield, W.K. (1982) Dynamic mechanical properties of some polycaprolactone-based, crosslinked, crystallizable polyurethanes. J. Macro-mol. Set, Chem., A17 (2), 297-309. 

COMPARISON OF HYDROLYTIC STABILITY OF POLYURETHANE ELASTOMERS BASED ON POLYETHER AND POLYCAPROLACTONE... 

Eyrich, D., Wiese, H., Mailer, G., Skodacek, D., Appel, B., Sarhan, H., et al., 2007. In vitro and in vivo cartilage engineering using a combination of chondrocyte-seeded long-term stable fibrin gels and polycaprolactone-based polyurethane scaffolds. Tissue Engineering 13 (9),... 

Meng Q, et al. Polycaprolactone-based shape memory segmented polyurethane fiber. J Appl Polym Sci 2007 106 2515-23. 

Asefnejad A, Khorasani MT, Behnamghader A, Farsadzadeh B, Bonakdar S. Manufacturing of biodegradable polyurethane scaffolds based on polycaprolactone using a phase separation method physical properties and in vitro assay. Int J Nanomed 2011 6 2375-84. 

Meng Q.H., Hu J., Zhu Y, Lu J. and Liu Y. (2007), Polycaprolactone-based shape memory segmented polyurethane fiber. Journal of Applied Polymer Science, 106 pp. 2515-2523. 

Among the polyurethane, polyester, and polyamide thermoplastic elastomers, those with polyether-based elastomer segments have better hydrolytic stabihty and low temperature flexibiUty, whereas polyester-based analogues are tougher and have the best oil resistance (43). Polycaprolactones and aUphatic polycarbonates, two special types of polyesters, are used to produce premium-grade polyurethanes (12). 

Thermoplastic polyurethane elastomers have now been available for many years (and were described in the first edition of this book). The adipate polyester-based materials have outstanding abrasion and tear resistance as well as very good resistance to oils and oxidative degradation. The polyether-based materials are more noted for their resistance to hydrolysis and fungal attack. Rather specialised polymers based on polycaprolactone (Section 25.11) may be considered as premium grade materials with good all round properties. 

In this chapter we investigate the morphology of a series of polyurethanes based on polycaprolactone polyol (PCP), diphenylmethane diisocyanate (MDI), and butanediol (BDO). Samples of as-batch-reacted and solution-cast polymers were examined by optical microscopy, transmission electron microscopy, electron and x-ray diffraction, and differential scanning calorimetry. Our interest is to provide a mapping of the size and shape of the domains (and any superstructure such as spherulites) and the degree of order as a function of the fraction of each phase present. 

Results qualitatively similar to those in Figure 2 were obtained with polyurethanes made from toluene dllsocyanate (TDI), BD, and 1) PCL 2000 2) a polycaprolactone diol of molecular weight 1220 (PCL 1220) 3) a polyethyleneadlpate diol of molecular weight 2000 (PEAD 2000). However, all TDI based polymers had very low stress values at 60 C. 

It is considered that the polyurethanes based on oleochemical polyols, dimer acids and dimer alcohols, PTHF and PC-polyols lead to polyurethanes with excellent hydrolytic stability. Polycaprolactone (PCL) polyols and poly (butylene adipate) lead to polyurethanes with good hydrolytic stability, but use of poly (diethylene glycol adipate) give polyurethanes with poor hydrolytic resistance. 

Besides melt intercalation, described above, in situ intercalative polymerization of E-caprolactone (e-CL) has also been used [231] to prepare polycaprolactone (PCL)-based nanocomposites. The in situ intercalative polymerization, or monomer exfoliation, method was pioneered by Toyota Motor Company to create nylon-6/clay nanocomposites. The method involves in-reactor processing of e-CL and MMT, which has been ion-exchanged with the hydrochloride salt of aminolauric acid (12-aminodecanoic acid). Nanocomposite materials from polymers such as polystyrene, polyacrylates or methacrylates, styrene-butadiene rubber, polyester, polyurethane, and epoxy are amenable to the monomer approach. 

Chemistry Polyurethane is produced by the reaction of a polyol with an diisocyanate (or in some instances a polyisocyanate) in the presence of catalysts. The polyols of choice are poly(propylene glycol), block copolymers of ethylene oxide (10-15%) with propylene oxide, or the newer polymer polyols (based on polymers such as polystyrene or styrene-acrylonitrile copolymer). Polyester diols such as polycaprolactone diol can be used in place of the polyether polyol in this reaction. The isocyanate of choice is a mixture of the 2,4 and 2,6 isomers of tolylene di-isocyanate in the ratio of 80 20, generally referred to as 80 20TDI. Other isocyanates such as diphenylmethane di-isocyanate (MDI), hexamethylene di-isocyanate (HMDI), and isophorone di-isocyanate (IPDI) are also used. A tin-based or amine catalyst is used to promote the reaction. Given the wide choice of reactants available, the reaction can yield foams with a range of different mechanical and thermal characteristics. 

The two series of polyurethanes and their physical properties are given in Tables 9.12 and 9.13 based, respectively, for (i) a polyester polyol class (polycaprolactone) and (ii) a polyether polyol class the diisocyanates used were CHDI and PPDI, respectively, chain-extended in various ways as shown. 

PROPERTIES OF THERMOPLASTIC POLYURETHANES BASED ON POLYCAPROLACTONE (POLYESTER) OF 2000 MOLECULAR WEIGHT... 

A representative example is the synthesis of amino acid based polyurethanes using L-tyrosine based chain extender, PEG and polycaprolactone diol as soft segments, and HDI and HMDI as diisocyanate components [38, 39]. By altering the soft and diisocyanate components, the researchers were able to prepare a number of polyurethanes with varying hydrophobicities and degradation behavior. 

Preparation of polycaprolactone and poly(ethylene glycol)-based alternating block polyurethanes... 

Chang Peter R., Ai Fujin, Chen Yun, Dufresne Alain, and Huang Jin. Effects of starch nano-crystal-graft-polycaprolactone on mechanical properties of waterborne polyurethane-based nanocomposites. J. Appl. Polym. Sci. Ill no. 2 (2009) 619-627. 

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