Polycarbonate ester

The reaction of CDI with a single mole of alcohol yields imidazole-iV-carboxyl-ates,t229H231] which by reaction with a second mole of alcohol lead to carbonic esters. With bifunctional alcohols CDI yields polycarbonic esters.[1-, C232]... 

Carbonic acid is a diacid with suitable diols, it can form polyesters. For example, when phosgene (the acid chloride of carbonic acid) reacts with a diol, the product is a polycarbonate ester). The following equation shows the synthesis of Lexan polycarbonate a strong, clear, and colorless material that is used for bulletproof windows and crash helmets. The diol used to make Lexan is a phenol called bisphenolA, a common intermediate in polyester and polyurethane synthesis. 

PC Bisphenol A polycarbonate PCE Polycarbonate ester copolymer PCL Polycaprolactone... 

Polyetherimide/ PCE, Polycarbonate ester Sabic Ultem AXlOO Partial miscibility Amorphous/ amorphous... 

Owing to their high Tg and the hydrolytic resistance of the aromatic sulfone backbone structure, polysulfones display reliable long-term performance in hot water and steam even under autoclave conditions. Unlike the other high-Tg, transparent polymers, such as polycarbonate (PC), polycarbonate-ester (PCE), and polyetherimides (PEI), the sulfone polymers are not prone to crazing and failure... 

Phase-separated PEI blends have been investigated. Combinations of PEI with polycarbonate (PC) or polycarbonate ester (PCE) copolymers have a fine, laminar two-phase morphology [36]. Combinations of PEI with polycarbonate or polyester carbonates yield a family of two-phase opaque systems that have reduced heat capability versus PEI, but show improved impact and better melt flow [37, 38]. 

Banner, M., and May, A., Injection Molding of a High Flow PEI-Polycarbonate Ester Blend, 62nd SPEANTEC, 2004, pp. 2854-2857. 

Gunduz, N., and Gallucci, R., Glass Filled Polycarbonate Ester-Polyetherimide Blends, 61st SPEANTEC, 2003, pp. 1842-1864. 

C.H. Schramm, and M. Zief, Resinous polycarbonate esters of cyclohexane-... 

Lexan is a polycarbonate ester condensation polymer that is transparent and nearly unbreakable. It is used in bulletproof windows (a one-inch-thick Lexan plate will stop a. 38-caliber bullet fired from 12 feet), football and motorcycle helmets, and the visors in astronauts helmets. It is made from the two monomers shown below. Draw two repeating units of this polymer. 

Ultem resin blends are designed to fill the gap between polycarbonate and polyetherimide resins. Key features are good flow, intermediate heat performance and price. Blends include Ultem 1285, Ultem ATX, a polycarbonate-ester blend, and Ultem HTX. 

Polycaprolactone diol Polycaprolate Polycarbamic esters Polycarbonate... 

Acrylic ESTER POLYMERS Acrylonitrile POLYMERS Cellulose esters). Engineering plastics (qv) such as acetal resins (qv), polyamides (qv), polycarbonate (qv), polyesters (qv), and poly(phenylene sulfide), and advanced materials such as Hquid crystal polymers, polysulfone, and polyetheretherketone are used in high performance appHcations they are processed at higher temperatures than their commodity counterparts (see Polymers containing sulfur). 

Solubility and Solvent Resistance. The majority of polycarbonates are prepared in methylene chloride solution. Chloroform, i7j -l,2-dichloroethylene, yy -tetrachloroethane, and methylene chloride are the preferred solvents for polycarbonates. The polymer is soluble in chlorobenzene or o-dichlorobenzene when warm, but crystallization may occur at lower temperatures. Methylene chloride is most commonly used because of the high solubiUty of the polymer (350 g/L at 25°C), and because this solvent has low flammabiUty and toxicity. Nonhalogenated solvents include tetrahydrofuran, dioxane, pyridine, and cresols. Hydrocarbons (qv) and aUphatic alcohols, esters (see Esters, organic), or ketones (qv) do not dissolve polycarbonates. Acetone (qv) promotes rapid crystallization of the normally amorphous polymer, and causes catastrophic failure of stressed polycarbonate parts. 

Noncrystalline aromatic polycarbonates (qv) and polyesters (polyarylates) and alloys of polycarbonate with other thermoplastics are considered elsewhere, as are aHphatic polyesters derived from natural or biological sources such as poly(3-hydroxybutyrate), poly(glycoHde), or poly(lactide) these, too, are separately covered (see Polymers, environmentally degradable Sutures). Thermoplastic elastomers derived from poly(ester—ether) block copolymers such as PBT/PTMEG-T [82662-36-0] and known by commercial names such as Hytrel and Riteflex are included here in the section on poly(butylene terephthalate). Specific polymers are dealt with largely in order of volume, which puts PET first by virtue of its enormous market volume in bottie resin. 

Eyeglass frames made of cellulose acetate plasticized with diglycerol esters do not exhibit opaqueness at the frame-lens junction with polycarbonate plastic lenses (146,147). 

Fig. 1. Engineering resins cost vs annual volume (11) (HDT, °C) A, polyetheretherketone (288) B, polyamideimide (>270) C, polyarylether sulfone (170- >200) D, polyimide (190) E, amorphous nylons (124) F, poly(phenylene sulfide) (>260) G, polyarylates (170) H, crystalline nylons (90—220) I, polycarbonate (130) J, midrange poly(phenylene oxide) alloy (107—150) K, polyphthalate esters (180—260) and L, acetal resins (110—140).

Polypropylene has a chemical resistance about the same as that of polyethylene, but it can be used at 120°C (250°F). Polycarbonate is a relatively high-temperature plastic. It can be used up to 150°C (300°F). Resistance to mineral acids is good. Strong alkalies slowly decompose it, but mild alkalies do not. It is partially soluble in aromatic solvents and soluble in chlorinated hydrocarbons. Polyphenylene oxide has good resistance to ahphatic solvents, acids, and bases but poor resistance to esters, ketones, and aromatic or chlorinated solvents. 

By reaction of polyhydroxy compounds with a carbonic acid derivative, a series of related polymers may be produced with carbonate (—0 C0 0—) linkages, the polymers being referred to as polycarbonates. Carbonic acid, C0(0H)2, itself does not exist in the free state but by means of ester exchange Figure 20.1) (1) and phosgenation techniques (II) it is possible to produce useful products. 

In 1930 Carothers and Natta prepared a number of aliphatic polycarbonates using ester-interchange reactions. These materials had a low melting point, were easily hydrolysed and did not achieve commercial significance. 

The chemical resistance of polyester materials is well recognised to be limited because of the comparative ease of hydrolysis of the ester groups. Whereas this ease of hydrolysis was also observed in aliphatic polycarbonates produced by... 

Unless the hydroxyl groups have such proximity that cyclisation takes place, polycarbonates will normally be produced whenever phosgene or a carbonate ester is reacted with a polyhydroxy compound. This means that a very large range of polycarbonate resins are possible and in fact many hundreds have been prepared. 

Aliphatic polycarbonates have few characteristics which make them potentially valuable materials but study of various aromatic polycarbonates is instructive even if not of immediate commercial significance. Although bisphenol A polycarbonates still show the best all-round properties other carbonic ester polymers have been prepared which are outstandingly good in one or two specific properties. For example, some materials have better heat resistance, some have better resistance to hydrolysis, some have greater solvent resistance whilst others are less permeable to gases. 

There has also been active interest in blends of PBT with other polymers. These include blends with PMMA and polyether-ester rubbers and blends with a silicone/polycarbonate block copolymer. 

Where transparency is required, a range of polymers is available. Polystyrene is the least expensive but polymethylmethacrylate has an outstanding high light transmission combined with excellent weathering properties. Also to be considered are the polycarbonates, glass-clear polyamides, SAN, butadiene-styrene block copolymers, MBS polymers, plasticised PVC, ionomers and cellulose esters such as cellulose acetate. 

All of the eommereial alkyl eyanoaerylate monomers are low-viseosity liquids, and for some applications this can be an advantage. However, there are instances where a viseous liquid or a gel adhesive would be preferred, sueh as for application to a vertical surface or on porous substrates. A variety of viscosity control agents, depending upon the desired properties, have been added to increase the viscosity of instant adhesives [21]. The materials, which have been utilized, include polymethyl methacrylate, hydrophobic silica, hydrophobic alumina, treated quartz, polyethyl cyanoacrylate, cellulose esters, polycarbonates, and carbon black. For example, the addition of 5-10% of amorphous, non-crystalline, fumed silica to ethyl cyanoacrylate changes the monomer viscosity from a 2-cps liquid to a gelled material [22]. Because of the sensitivity of cyanoacrylate esters to basic materials, some additives require treatment with an acid to prevent premature gelation of the product. 

Cellulose Esters Epoxy Resins Lignins Polystyrene Poly (2-vinyl pyridine) Polyvinyl Chloride Polymethyl methacrylate Polyphenylene Oxide Phenolics Polycarbonate Polyvinyl Acetate, etc. Polyvinyl butyral SBR rubber, etc., etc. 

Nearly all of the polymers produced by step-growth polymerization contain heteroatoms and/or aromatic rings in the backbone. One exception is polymers produced from acyclic diene metathesis (ADMET) polymerization.22 Hydrocarbon polymers with carbon-carbon double bonds are readily produced using ADMET polymerization techniques. Polyesters, polycarbonates, polyamides, and polyurethanes can be produced from aliphatic monomers with appropriate functional groups (Fig. 1.1). In these aliphatic polymers, the concentration of the linking groups (ester, carbonate, amide, or urethane) in the backbone greatly influences the physical properties. 

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