Polyester Carbonates and Block Copolymers

In addition to standard grades varying in the ABS/PC ratio, fire-retarded, glass-fibre-reinforced and glass-fibre-reinforced fire-retarded grades are available. Typical properties of three grades of ABS-PC alloys are given in Table 20.9. 

Polycarbonate-polyethylene terephthalate (PC-PET) alloys have also recently been announced by DSM. 

Polycarbonates based on tetramethylbisphenol A are thermally stable and have a high Vicat softening point of 196°C. On the other hand they have lower impact and notched impact resistance than the normal polymer. Blends with styrene-based polymers were introduced in 1980, and compared with PC/ABS blends, are claimed to have improved hydrolytic resistance, lower density and higher heat deflection temperatures. Suggested applications are as dishes for microwave ovens and car headlamp reflectors. 

Yet another recent development has been the alloying of polycarbonates with liquid crystal polymers such as Vectra (see Section 25.8.1). These alloys are notable for their very good flow properties and higher strength and rigidity than conventional bisphenol A polycarbonates. 

In the 1980s a number of copolymers became established, known as polyester carbonates, which may be considered as being intermediate between bisphenol A polycarbonates and the polyarylates discussed in Chapter 25. 

Polyester Carbonates and Block Copolymers 579 Table 20.9 Selected properties of PC-ABS and PC-PBT alloys 

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Today about 75% of the market is held by General Electric and Bayer with their products Lexan and Makrolon respectively. Other manufacturers are ANIC (Italy), Taijin Chemical Co., Mitsubishi Edogawa and Idemitsu Kasei in Japan and, since 1985, Dow (USA) and Policarbonatos do Brasil (Brazil). Whilst this market is dominated by bis-phenol A polycarbonates, recent important developments include alloys with other thermoplastics, polyester carbonates and silicone-polycarbonate block copolymers. 

Recently, various polyesters such as poly(ethylene adipate), poly(tetramethylene adipate), poly(caprolac-tone), and poly(aliphatic carbonate), having terminal hydroxyl groups, were reacted with ACPC to give corresponding macroazoesters and their thermal behaviors were observed by DSC [14]. The block copolymers of these polycondensation polymers with addition polymers such as PSt and PMMA were synthesized [14]. 

See also PBT degradation structure and properties of, 44-46 synthesis of, 106, 191 Polycaprolactam (PCA), 530, 541 Poly(e-caprolactone) (CAPA, PCL), 28, 42, 86. See also PCL degradation OH-terminated, 98-99 Polycaprolactones, 213 Poly(carbo[dimethyl]silane)s, 450, 451 Polycarbonate glycols, 207 Polycarbonate-polysulfone block copolymer, 360 Polycarbonates, 213 chemical structure of, 5 Polycarbosilanes, 450-456 Poly(chlorocarbosilanes), 454 Polycondensations, 57, 100 Poly(l,4-cyclohexylenedimethylene terephthalate) (PCT), 25 Polydimethyl siloxanes, 4 Poly(dioxanone) (PDO), 27 Poly (4,4 -dipheny lpheny lpho sphine oxide) (PAPO), 347 Polydispersity, 57 Polydispersity index, 444 Poly(D-lactic acid) (PDLA), 41 Poly(DL-lactic acid) (PDLLA), 42 Polyester amides, 18 Polyester-based networks, 58-60 Polyester carbonates, 18 Polyester-ether block copolymers, 20 Polyester-ethers, 26... 

Short fiber reinforcement of TPEs has recently opened up a new era in the field of polymer technology. Vajrasthira et al. [22] studied the fiber-matrix interactions in short aramid fiber-reinforced thermoplastic polyurethane (TPU) composites. Campbell and Goettler [23] reported the reinforcement of TPE matrix by Santoweb fibers, whereas Akhtar et al. [24] reported the reinforcement of a TPE matrix by short silk fiber. The reinforcement of thermoplastic co-polyester and TPU by short aramid fiber was reported by Watson and Prances [25]. Roy and coworkers [26-28] studied the rheological, hysteresis, mechanical, and dynamic mechanical behavior of short carbon fiber-filled styrene-isoprene-styrene (SIS) block copolymers and TPEs derived from NR and high-density polyethylene (HOPE) blends. 

To bring the nanocontainer to a specific place where it should release its pay-load, targeting is a required approach. Hence, much work has been carried out to attach ligands or antibodies to the hydroxyl end-group of PEG-based assemblies [150,181,243], Biotinylated nondegradable block copolymer assemblies have been shown to attach to surfaces coated with the biotin receptor avidin [146,147, 150,244], Coupling chemistry has been applied to conjugate either an antihuman IgG, or antihuman serum to PEG-carbonate- or PEG-polyester-assembled polymer vesicles [149,245], HIV-derived Tat peptide attached to PEG-PBD polymersomes enhanced the cellular delivery of nanoparticles [246] and increased dendritic cell uptake in vitro [181]. 

The block-copolymers of polysulfone and polyesters can be also produced [188] by the reaction of aromatic polysulfones in environment of dipolar aprotone dissolvents (dimethylsulfoxide, N-methylpirrolydone, N-methylcaprolactam, N, N -dimethylacetamides or their mixes) with alyphatic polyesters containing not less than two edge OH-groups in the presence of basic catalyst - carbonates of alkali metals Li, Na, K. 

Common SS include polyethers, polyesters and polyalkyl glycols with glass transition temperatures in the range of -70°to -30°C. Commonly used macrodiols in the PUs synthesis are polyalkyl-diols, such as polyisobutylene diol [70], polybutadiene (PBU) [20, 71], or oligo-butadiene diols [72] as well as hydrogenated polybutadiene diol [20] polyether diols polytetrahydrofuran (PTHF or PTMO) [50-52], polyethylene glycol (PEG) or (PEO) [73], polypropyleneoxide (PPO) [73] or mixed blocks of them PEO-PPO-PEO [74] and PPO-THF [54] polyester diols poly(ethylene adipate) (PEA) [4,20], poly(butylene adipate) (PBA) [20, 73], and latterly polycaprolactone diol (PCL or PCD) [75], polyalkylcarbonate polyol [20] or mixed blocks of them, for example poly(carbonate-co-ester)diol [76], poly(hexamethylene-carbonate)diol [77], as well as poly(hexamethylene-carbonate-co-caprolactone)diol [78] and a mixed block copolymer of polyether and polyester blocks PCL-b-PTHF-b-PCL [79]. Examples schemes of macrodiols are shown in Eig. 1.9. 

Demulsifiers synthesized by polycondensation of an ethylene oxide-propylene oxide block copolymer, an oxalkylated fatty amine, and a dicarboxylic acid are known as polyester amines. These demulsifiers have the ability to adhere to natural substances that stabilize emulsions, such as organic materials formed by asphaltenes, oil resins, naphthenic acids, paraffins, and waxes they also adhere to inorganic particles formed by clays, carbonates, silica, and metallic salts. These properties increase the demulsification efficiency of the polyester amines [2, 5]. The availability of a variety of building blocks allows for the preparation of demulsifiers for specific applications. With this chemicd arsenal it is possible to tailor demulsifiers for nearly all problems posed by stable emulsions, including crude oil dehydration and desalting. 

Materials studied include polyesters and polyethers [73], PMMA [74], star-shaped styrene block copolymers [75, 76], PC [77], isoprene-styrene graft copolymers [76], polyethylene oxide-maleic anhydride-vinyl methyl ether copolymers [78], polybutylene terephthalate [79], PE [80], (phenoxymethyl)thizrane [81], polytrimethylene carbonate [82], polybutylene succinate [83], polymethyldiundecenylsilane [84], poly(N-vinyl carbazole) [85], titanium-containing copolymers [86], styrene-macro zwitterion polymers [87], and poly(octadecene-alt-maleic anhydride) [88]. 

Block copolymers of silicone, generally polydlmethylsiloxane, and organic blocks such as styrenic, urethane, carbonate, imide, amide and polyester yield a wide range of materials both thermoplastic and thermosetting with tensile strengths as high as 50 MPa while maintaining many of... 

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