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Carbonate urethane

Although polymers in-service are required to be resistant toward hydrolysis and solar degradation, for polymer deformulation purposes hydrolysis is an asset. Highly crystalline materials such as compounded polyamides are difficult to extract. For such materials hydrolysis or other forms of chemolysis render additives accessible for analysis. Polymers, which may profitably be depolymerised into their monomers by hydrolysis include PET, PBT, PC, PU, PES, POM, PA and others. Hydrolysis occurs when moisture causes chain scissions to occur within the molecule. In polyesters, chain scissions take place at the ester linkages (R-CO-O-R ), which causes a reduction in molecular weight as well as in mechanical properties. Polyesters show their susceptibility to hydrolysis with dramatic shifts in molecular weight distribution. Apart from access to the additives fraction, hydrolysis also facilitates molecular characterisation of the polymer. In this context, it is noticed that condensation polymers (polyesters, -amides, -ethers, -carbonates, -urethanes) have also been studied much... [Pg.152]

Uses Manufacture of acrylonitrile, hydrazine hydrate, hydrogen cyanide, nitric acid, sodium carbonate, urethane, explosives, synthetic fibers, fertilizers refrigerant condensation catalyst dyeing neutralizing agent synthetic fibers latex preservative fuel cells, rocket fuel nitrocellulose nitroparaffins ethylenediamine, melamine sulfite cooking liquors developing diazo films yeast nutrient. [Pg.99]

The synthesis of 2(3//)-oxazolones by incorporation of carbon atom 2 into a four-atom chain is exemplified by the condensation of phenacylaniline with ethyl chloroformate (equation 138). Benzoxazolones are similarly prepared from o-aminophenols and derivatives of carbonic acid, such as phosgene, diethyl carbonate, urethane (Et02CNH2) or urea (equation 139). The analogous condensation of carbon disulfide or cyanogen bromide with o-aminophenols leads to benzoxazolethiones or 2-aminobenzoxazoles, respectively (equation 140). [Pg.224]

The results for a Py-GC/MS analysis of a carbonate urethane copolymer are shown below for poly[(1,6-hexyl-1,2-ethyl carbonate)diol 4,4 -methylenebis(phenyl isocyanate)]-co-[1,4-butandiol 4,4 -methylenebis(phenyl isocyanate)]. The idealized structure for this copolymer is shown below ... [Pg.567]

Figure 11.1.6. Result for a Py-GC/MS analysis of a carbonate urethane soft copolymer, M = 264,000. Pyrolysis done on 0.4 mg material at 600° C in He, with the separation on a Carbowax type column. Figure 11.1.6. Result for a Py-GC/MS analysis of a carbonate urethane soft copolymer, M = 264,000. Pyrolysis done on 0.4 mg material at 600° C in He, with the separation on a Carbowax type column.
A urethane—also called a carbamate—is a compound that has an OR group and an NHR group bonded to the same carbonyl carbon. Urethanes can be prepared by treating an isocyanate with an alcohol. [Pg.1167]

Passive hydrolysis. Esters, carbonates, amides and urethanes are susceptible to hydrolysis. Drugs linked with the spacer via such bonds will be released in aqueous media. The rate of release will decrease in the order ester > carbonate > urethane > amide. Cleavage may also occur at the level of the spacer-backbone bond so that spacer-drug moieties can be released as well. [Pg.591]

E. Christenson, M. Dadsetan, M. Wiggins, J. Anderson, A. Hiltner, Poly(carbonate urethane) and poly(ether urethane) biodegradation in vivo studies, J. Biomed. Mater. Res. A 69 (3) (2004) 407-416. [Pg.141]

H. Yi, G. Jianjun, L.F. Kazuro, H. Ryotaro, L.R Anca, R.W. William, Tailoring the degradation kinetics of poly(ester carbonate urethane)urea thermoplastic elastomers for tissue engineering scaffolds, Biomaterials il (15) (2010) 4249 258. [Pg.143]

S. Hsu, C. Chen, C. Chao, C. Chen, J. Chiu, Cell migration on nanophase-separated poly(carbonate urethane)s, J. Med. Biol. Eng. 27 (1)... [Pg.307]

E.M. Christenson, P. Sachin, M. James Anderson, H. Anne, Enzymatic degradation of poly (ether urethane) and poly (carbonate urethane) by cholesterol esterase. Biomaterials 27, 3920-3926 (2006)... [Pg.262]

Khang D, Kim SY, Liu-Snyder P, Palmore GT, Durbin SM, Webster TJ. Enhanced fi-bronectin adsorption on carbon nanotube/poly(carbonate) urethane independent role of surface nano-roughness and associated surface energy. Biomaterials 2007 28 4756-68. [Pg.180]

Phaneuf MD. Szycher M, Berceli SA, Dempsey DJ, Quist WC, LoGerfo FW. Covalent linkage of recombinant hirudin to a novel ionic poly (carbonated) urethane polymer with protein binding sites determination of surface anti-thrombic activity. Artif. Organs 22 657-665,1998. [Pg.804]

A non-biodegradable nanocomposite based on polyhedral oligomeric silsesquioxane nanocages with poly(carbonate urethane) has been developed (33). A good ceU-compatibility and antithrombo-genic properties have been noticed. [Pg.325]

Type Poly- ethylene Chlorinated Rubber Chlorosul-fonated Chloro- Polyethy-prene lene Eluoro- carbon Urethane Vinyl Vinyl- Alkyd (Approx 1 1) Polyester Alkyd (Oil-free) Acrylic (Thermo- setting)... [Pg.773]

PCU/EVA polymer blend consisting of poly(carbonate urethane) and... [Pg.3]

Poly(ether urethanes) are of special interest due to their good mechanical properties, broad synthetic possibilities, and rather good blood compatibility for medical applications, e.g. catheters, heart valves [47]. A poly(carbonate urethane) (PCU) comprising poly(hexamethylene carbonate), the aromatic diisocyanate 4,4 -diphenylmethane diisocyanate (MDI) and 1,4-butanediol as chain prolonger has been developed (Table 2) [133]. [Pg.37]

Wang F, et al. Synthesis, characterization and surface modification of low moduli poly(ether carbonate urethane)ureas for soft tissue engineering. Acta Biomater 2009 5(8) 2901-12. [Pg.22]

Labow RS, Meek E, Santerre IP. Hydrolytic degradation of poly(carbonate)-urethanes by monocyte-deiived macrophages. Biomaterials November 2001 22(22) 3025-33. [Pg.105]

Christenson EM, Anderson JM, Hiltner A. Antioxidant inhibition of poly(carbonate urethane) in vivo biodegradation. J Biomed Mater Res A March 1, 2006 76(3) 480-90. [Pg.109]

Fare S, Petrini P, Motta A, Cigada A, Tanzi M. Synergistic effects of oxidative environments and mechanical stress on in vitro stability of poly(ether urethanes) and poly(carbonate urethanes). J Biomed Mater Res 1999 45(1) 62—74. [Pg.167]

Hsn SH, Kao YC. BiocompatibUity of poly(carbonate urethane)s with various degrees of nanophase separation. Macromol Biosci 2005 5(3) 246-53. [Pg.167]

See other pages where Carbonate urethane is mentioned: [Pg.213]    [Pg.505]    [Pg.396]    [Pg.15]    [Pg.38]    [Pg.116]    [Pg.119]    [Pg.1023]    [Pg.505]    [Pg.123]    [Pg.124]    [Pg.126]    [Pg.127]    [Pg.127]    [Pg.8]    [Pg.782]    [Pg.3]    [Pg.78]    [Pg.93]    [Pg.106]    [Pg.150]    [Pg.167]   
See also in sourсe #XX -- [ Pg.567 ]



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Carbonic acid anhydrides urethans

Carbonic acid esters urethans

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