Poly Preforming

Preformed functional poly- Preformed functional poly-... 

Soft-drink bottles made from poly(ethylene terephthalate) (PET) are usuady made by stretch-blow mol ding in a two-step process. Eirst, a test-tube-shaped preform is molded, which is then reheated to just above its glass-transition temperature, stretched, and blown. Stretching the PET produces biaxial orientation, which improves transparency, strength, and toughness of the botde (54,56). A one-step process is used for many custom containers that are injection stretch-blow molded. 

Eatty acid ethoxylates are used extensively in the textile industry as emulsifiers for processing oils, antistatic agents (qv), softeners, and fiber lubricants, and as detergents in scouring operations. They also find appHcation as emulsifiers in cosmetic preparations and pesticide formulations. Eatty acid ethoxylates are manufactured either by alkaH-catalyzed reaction of fatty acids with ethylene oxide or by acid-catalyzed esterification of fatty acids with preformed poly(ethylene glycol). Deodorization steps are commonly incorporated into the manufacturing process. 

Perhaps the most thoroughly investigated approach is the modification of preformed polymers in particular poly(vinyl isocyanate) and polyacrylonitrile Figure 29.21). 

Diphenol/thiophenol is one of the most important polymer precursors for synthesis of poly(aryl ethers) or poly-(aryl sulfides) in displacement polymerizations. Commonly used bisphenols are 4,4 -isopropylidene diphenol or bisphenol-A (BPA) due to their low price and easy availability. Other commercial bisphenols have also been reported [7,24,25]. Recently, synthesis of poly(aryl ethers) by the reaction of new bisphenol monomers with activated aromatic dihalides has been reported. The structures of the polymer precursors are described in Table 2. Poly(aryl ether phenylquinoxalines) have been synthesized by Connell et al. [26], by the reaction of bisphenols containing a preformed quinoxaline ring with... 

Concerning the reaction of ACPC with diols, the frequent use of poly(ethylene glycol) has to be mentioned [20-24]. Ueda et al. ([22-24]) reacted preformed poly(ethylene glycol) (Mn between 6 x 10 to 2 x 10 ) with ACPC. In this case, unlike the reaction of ACPA with diols vide ante), no additional condensation agent was needed. The ethylene glycol-based thermally labile polymers were used to produce blocks with poly(vinyl chloride) [22], poly(styrene) [23], poly(methyl acrylate), poly(vinyl acetate), and poly(acrylonitrile) [24]. 

Apart from poly(ethylene glycol), other hydroxyl-terminated polymers and low-molecular weight compounds were condensed with ACPC. An interesting example is the reaction of ACPC with preformed poly(bu-tadiene) possessing terminal OH groups [26]. The reaction was carried out in chloroform solution and (CH3CH2)3N was used as a catalyst. MAIs based on butadiene thus obtained were used for the thermally induced block copolymerization with styrene [26] and dimethyl itaconate [27]. 

Yagci and Deniziigil [44] applied the method of partial decomposition of MAIs introducing styrene and methyl methacrylate blocks into poly(amide)s. The poly-(amide)-based MAI had been prepared by a reaction of AIBN with formaldehyde (see Scheme 10). Evidently, since each unit of the preformed MAI carries one azo group, there are enough azo sites in every MAI molecule for a controlled and adjustable partial decomposition. 

ABA type poly(hydroxyethyl methacrylate) (HEMA) and PDMS copolymers were synthesized by the coupling reactions of preformed a,co-isocyanate terminated PDMS oligomers and amine-terminated HEMA macromonomers312). Polymerization reactions were conducted in DMF solution at 0 °C. Products were purified by precipitation in diethyl ether to remove unreacted PDMS oligomers. After dissolving in DMF/toluene mixture, copolymers were reprecipitated in methanol/water mixture to remove unreacted HEMA oligomers. Microphase separated structures were observed under transmission electron microscope, using osmium tetroxide stained thin copolymer films. 

In a typical reaction 100 - 200 mg of metal [Cr or Ni] was evaporated from a preformed alumina crucible over a period of 60 - 90 min and deposited into a mixture of 2 in poly(dimethylsiloxane) [Petrarch Systems 0.1 P.] within a rotary solution metal vapor reactor operating at 10 4 torr. The reaction flask was cooled to approximately 270 K by an iced-water bath. For a description of the apparatus see Chapter 3 of reference 4. The product in each case was a dark orange viscous liquid and was characterized as obtained from the reaction vessel. 

Derivatization reactions. In addition to changing the substituents in the primary precursor phosphines, (MegSi)2NPRR , two other approaches have been used to prepare polymers with more complex substituents attached to the backbone by direct P-C linkages. These are (a) alteration of R and R in the immediate N-silylphosphoranimine precursors, MegSiN=P(OOUCFo)RR , and (b) alteration of R and R in the preformed poly(alkyl/aryl-phosphazenes), (RR P=N]n. Some examples of the former method are described below and in other papers (21-23), while the use of the latter approach to prepare several silylated poly(alkyl/arylphosphazenes) has been recently reported. (20)... 

In addition to providing many new precursors to functionalized poly(alkyl/arylphosphazenes), the deprotonation/substitution reactions of these N-silylphosphoranimines serve as useful models for similar chemistry that can be carried out on the preformed polymers. New reactions and experimentation with reaction conditions can first be tried with monomers before being applied to the more difficult to prepare polymeric substrates. A considerable amount of preliminary work [e.g., with the silylated monomers (z z) and polymers (2 o) has demonstrated the feasibility of this model system approach. 

The sol-gel methodology can also be applied to non-hydrolytic processes. The preparation of methylsilsesqui-oxane-titanium oxide hybrid by the etherolysis-condensation of a mixture of methyltrichlorosilane and metal chloride,353 354 and by the condensation of preformed poly(methylsilsesquioxane) carrying Si-OH and Si-OCHj groups with titanium(iv) -butoxide,355 has been reported. 

For the polymerisation of styrene (SnC -F O-PhNC -CC at 0°) kjkv for anisole was found [85] to be 1.62. It is highly probable that the big difference between this and the value for isobutene reflects mainly the difference between the ps for the two monomers. The very low value of kjkv in the polymerisation of isobutene - or the very large kv of isobutene - accounts for the observation [86] that, whereas styrene polymerising cationically in the presence of preformed poly-p-methoxystyrene will form grafts by reacting with pendent rings, isobutene will not do so. 

The procedures described are based on improved modifications from original publications [4-8]. They focus on the divergent excess reagent syntheses of dendri-poly(amidoamines) using various alkylenediamine cores. Examples of both divergent in situ branch cell methods, as well as divergent preformed branch cell methods are presented. 

Grafting of these preformed monoliths with dormant radicals is achieved by filling the pores with a monomer solution and heating to the desired temperature to activate the capped radicals. For example, a functionalization of poly(styrene-divinylbenzene) monolith with chloromethylstyrene and vinyl-pyridine to obtain material with up to 3.6 mmol/g of functionalities has been demonstrated [88]. 

Other, rigid-rod monomers can be incorporated into PET, to increase chain stiffness, and therefore the Tg (Figure 6.5). A prime example of such a rigid copolyester is a multi-ring poly(ethylene terephthalate-imide) [43], As was the case with the polyesteramides of Gaymans, the imide-containing diol monomer, A,A-bis[p-(2-hydroxyethoxycarbonyl)phenyl]-biphenyl-3,3,4,4-tetracarboxy-diimide, was preformed prior to polycondensation, where this monomer is free... 

Previous work on the synthesis of TTF (tetrathiafulvalene) containing polymers has been reported by at least seven groups of researchers. Most of this work concerns condensation 6,7,8,9 polymers or polymers made from vinyl substituted TTF molecules . Without exception, the polymers produced by these methods have been largely unacceptable for subsequent physical study because of their brittle,intractable, highly insoluble nature. Only by reaction of a suitably monofunctionalized TTF derivative with the preformed polymer poly(vinylbenzylchloride) has it been found possible — to prepare soluble TTF homopolymers with more manageable physical properties. 

Another approach was attempted by Seppala and Kylma who reported the synthesis of poly(ester-urethane)s by condensation of hydroxyl terminated tel-echelic poly(CL-co-LA) oligomers with 1,6-hexamethylene diisocyanate (Scheme 33) [94]. The diisocyanate acts as chain extender producing an increase in molecular weight of the preformed oligomers. The authors claim that some of the copolymers present elastomeric properties. Using a similar method. Storey described the synthesis of polyurethane networks based on D,L-LA, GA, eCL,... 

---