Hydroxy-terminated

CTPB = carboxy-terminated polybutadiene HTPB = hydroxy-terminated polybutadiene PBAN = polybutadiene-acrylic acid-acrylonitrile and PBAA = polybutadiene-acrylic acid. 

The maleimide is prebuilt into the molecule in a separate step. Maleimidobenzoic acid [17075-07-7] or its acid haUde was used to synthesize maleintide-terrninated polyamides (16,17) or polyesters (27) from amino- or hydroxy-terminated polyamides and polyesters, respectively. The Hterature on bismaleimide prepolymers and bismaleimide building blocks is quite extensive (28), but only a limited number of BMI building blocks have been used for commercial resin formulations. 

Heat-resistant resin compositions based on bismaleknide—epoxy blends are achieved by reaction of a BMI—y -aminophenol [591-27-5] (1 1) adduct with epoxy. This prepolymer is fully cured with an imida2ole catalyst (54). Blends of hydroxy-terminated BMI—aminophenol adducts can easily be B-staged, that is, prepolymerked, and subsequendy ground to provide a powder that can be molded by the appHcation of heat and pressure. 

Liquid organic rubbers with reactive functionality can be prepared by several methods. End-functional oligomers are preferred. Chains attached to the network at only one end do not contribute as much strength to the network as those attached at both ends [34], Urethane chemistry is a handy route to such molecules. A hydroxy-terminated oligomer (commonly a polyester or a polyether) can be reacted with excess diisocyanate, and then with a hydroxy methacrylate to form a reactive toughener [35]. The methacrylate ends undergo copolymerization with the rest of the acrylic monomers. The resulting adhesive is especially effective on poIy(vinyl chloride) shown in Scheme 2. 

A hydroxy-terminated oligomer can be converted into a carboxy-terminated one by reaction with an anhydride [37]. Such an oligomer can also be used to synthesize a methacrylated rubber as above [38]. 

Predominantly di-end-functional polymers may be prepared by conducting polymerizations with high concentrations of a functional initiator. Some of the first commercial products of this class, carboxy and hydroxy-terminated polybutadienes, were produced by this route.194... 

Many examples exist where a polymerization has been continued by ATRP. V" Often the procedure involves functionalization of a hydroxy-terminated polymer with bromoisobutyroyl (BriBBr, 314) or bromoisopropionoyl (BriPBr, 315) bromide. Examples include polyethylene oxide)044,646 and polypropylene... 

For example, using hydroxy-terminated polybutadiene as the binder, RDX as the expl, toluenediisocyanate as a co-polymer, sym-di-(2-naphthyl)-p-phenylenediamine as an antioxidant, and poly butene as the plasticizer in a wt % ratio of 12.1/42.7/5/0.2/40, a castable expl is produced. 

Synthesis and Characterisation of Hydroxy-Terminated Polybutadienes , Report No 6/R/66, ERDE, Waltham Abbey, Essex (Engl) (1967)... 

Low-Temperature Differential Thermal Analysis of Hydroxy-Terminated and Carboxy-Termi-nated Polybutadiene , Rept No CRREL-SR-149 (1970) 7a) H.F. Mark, Ed, Encyclopedia of... 

M.B. Frankel et al, Smokeless Composite Propellants Containing Carboxy- or Hydroxy-Terminated Polymers and a Nitroorganic Oxidizer , USP 3853646 (1974) CA 83, 12972 (1975) 37) A. Reichel et al, High Explo-... 

Composite proplnts, which are used almost entirely in rocket propulsion, normally contain a solid phase oxidizer combined with a polymeric fuel binder with a -CH2—CH2— structure. Practically speaking AP is the only oxidizer which has achieved high volume production, although ammonium nitrate (AN) has limited special uses such as in gas generators. Other oxidizers which have been studied more or less as curiosities include hydrazinium nitrate, nitronium perchlorate, lithium perchlorate, lithium nitrate, potassium perchlorate and others. Among binders, the most used are polyurethanes, polybutadiene/acrylonitrile/acrylic acid terpolymers and hydroxy-terminated polybutadienes... 

Another class of hydrocarbon binders used in propints are the carboxy-terminated polybutadiene polymers which are cross-linked with either tris[l-(2-methyl)aziridinyl] phosphine oxide (MAPO) or combinations with phenyl bis [l -(2-methyl)aziridinyl] phosphine oxide (Phenyl MAPO). Phenyl MAPO is a difunctional counterpart of MAPO which makes possible chain extension of polymers with two carboxylic acid groups. A typical propint formulation with ballistic properties is in Table 11 (Ref 83) Another class of composites includes those using hydroxy-terminated polybutadienes cross-linked with toluene diisocyanate as binders. The following simplified equations illustrate typical reactions involved in binder formation... 

Hydroxy-Terminated Poly butadiene Propellant Formulation... 

The influence of ambient aging at 70°F and accelerated aging at 160°F on the stress-strain behavior of carboxy-terminated polybutadiene, polybutadiene-acrylic acid, polybutadiene-acrylic acid-acrylonitrile, and hydroxy-terminated polybutadiene composite propints is shown in Figures 10 and 11. The elastomers and curative agents for these formulations are listed below... 

Hie most representative member of this class of polyesters is the low-molar-mass (M 1000-3000) hydroxy-terminated aliphatic poly(2,2/-oxydiethylene adipate) obtained by esterification between adipic acid and diethylene glycol. This oligomer is used as a macromonomer in the synthesis of polyurethane elastomers and flexible foams by reaction with diisocyanates (see Chapter 5). Hydroxy-terminated poly(f -caprolactonc) and copolyesters of various diols or polyols and diacids, such as o-phthalic acid or hydroxy acids, broaden the range of properties and applications of polyester polyols. 

Polyester polyols account for only ca. 10% of the total polyol market, which is dominated by polyether polyols such as hydroxy-terminated polyoxyethylene or polyoxypropylene. Polyester polyols are preferred for applications where better mechanical properties, wear resistance, and UV stability are required. The largest application of polyester polyols is flexible specialty polyurethane foam in the furniture, packaging, and automotive industries. Polyester polyols are also used for nonfoam applications such as coatings, paints, sealants, and adhesives 47... 

Polyester-based networks are typically prepared from polyester prepolymers bearing unsaturations which can be crosslinked. The crosslinking process is either an autoxidation in the presence of air oxygen (alkyd resins) or a copolymerization with unsaturated comonomers in the presence of radical initiators (unsaturated polyester resins). It should also be mentioned that hydroxy-terminated saturated polyesters are one of the basis prepolymers used in polyurethane network preparation (see Chapter 5). 

Lipases have also been used as initiators for the polymerization of lactones such as /3-bu tyro lac tone, <5-valerolactone, e-caprolactone, and macrolides.341,352-357 In this case, the key step is the reaction of lactone with die serine residue at the catalytically active site to form an acyl-enzyme hydroxy-terminated activated intermediate. This intermediate then reacts with the terminal hydroxyl group of a n-mer chain to produce an (n + i)-mer.325,355,358,359 Enzymatic lactone polymerization follows a conventional Michaelis-Menten enzymatic kinetics353 and presents a controlled character, without termination and chain transfer,355 although more or less controlled factors, such as water content of the enzyme, may affect polymerization rate and the nature of endgroups.360... 

In a similar way, polyester block copolymers were obtained by reacting acid chloride-terminated polyesters with hydroxy-terminated polyethers,401 or by reacting polyester-containing polymer mixtures with coupling agents such as diisocyanates.402... 

Poly(poly(alkylene terephthalate)-Woc -poly(oxyalkylene)) thermoplastic elastomers are prepared by the bulk polycondensation of dimethyl terephthalate with a mixture of 1,4-alkanediol and hydroxy-terminated poly(oxyalkylene) in... 

Preparation of polyfethylene oxide) (PEO) and poly(arylene ether) based hydrophilic-hydrophobic block copolymer is of special interest because PEO has been proven to be particularly reliable and versatile for the surface modification of biomaterials. The first poly(ediylene oxide)-/ /oc/c-polysulfonc (PEO-fc-PSF) copolymers were reported by Aksenov et al.217 They employed diisocyanate chemistry to link hydroxy-terminated sulfone oligomers and polyfethylene... 

Acid anhydride-diol reaction, 65 Acid anhydride-epoxy reaction, 85 Acid binders, 155, 157 Acid catalysis, of PET, 548-549 Acid-catalyzed hydrolysis of nylon-6, 567-568 of nylon-6,6, 568 Acid chloride, poly(p-benzamide) synthesis from, 188-189 Acid chloride-alcohol reaction, 75-77 Acid chloride-alkali metal diphenol salt interfacial reactions, 77 Acid chloride polymerization, of polyamides, 155-157 Acid chloride-terminated polyesters, reaction with hydroxy-terminated polyethers, 89 Acid-etch tests, 245 Acid number, 94 Acidolysis, 74 of nylon-6,6, 568... 

Hydroxyphenylimide, polybenzoxazole synthesis via, 318 Hydroxy-terminated hyperbranched polyesters, 32... 

Anionic polymerization of lactams was shown to proceed according to what is called the activated monomer mechanism. With bischloroformates of hydroxy-terminated poly(tetramethyleneglycol) and poly(styrene glycol) as precursors for a polymeric initiator containing N-acyl lactam ends, block copolymers with n-pyrrol-idone and e-caprolactam were obtained by bulk polymerizations in vacuum at 30 and 80 °C, respectively361. ... 

Synthesis of hydrolytically stable siloxane-urethanes by the melt reaction of organo-hydroxy terminated siloxane oligomers with various diisocyanates have been reported i97,i98) -yhg polymers obtained by this route are reported to be soluble in cresol and displayed rubber-like properties. However the molecular weights obtained were not very high. A later report56) described the use of hydroxybutyl terminated disiloxanes in the synthesis of poly(urethane-siloxanes). No data on the characterization of the copolymers have been given. However, from our independent kinetic and synthetic studies on the same system 199), unfortunately, it is clear that these types of materials do not result in well defined multiphase copolymers. The use of low molecular weight hydroxypropyl-terminated siloxanes in the synthesis of siloxane-urethane type structures has also been reported 198). 

The anionic method of polymerization is most useful for the synthesis of low molecular weight hydroxy-terminated oligomers and polymers that are to be further processed. For example, the treatment of hydroxy-terminated oligomers with isocyanates has been used to obtain polyester-urethanes (9,20), while triblock copolymers (PCL-PEG-PCL) are prepared by initiating the polymerization of e-caprolactone with the disodium alcoholate from polyethylene glycol (26). 

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