Poly infusion containers

The ability of some macromolecules to adsorb at interfaces is made use of in suspension and emulsion stabilisation (see Chapter 7). Gelatin, acacia, poly(vinyl alcohol) and proteins adsorb at interfaces. Sometimes such adsorption is unwanted, as in the case of insulin adsorption onto glass infusion bottles and poly(vinyl chloride) infusion containers and tubing used in giving sets. Adsorption of insulin to glass bottles and plastic i.v. tubing at slow rates of infusion is well documented. It... 

Statistical copolymerization of ethylene glycol and 1,4-butanediol with dimethyl ter-ephthalate results in products with improved crystallization and processing rates compared to poly(ethylene terephthalate). Polyarylates (trade names Ardel, Arylon, Durel), copolymers of bisphenol A with iso- and terephthalate units, combine the toughness, clarity, and proce-sibility of polycarbonate with the chemical and heat resistance of poly(ethylene terephthalate). The homopolymer containing only terephthalate units is crystalline, insoluble, sometimes infusible, and difficult to process. The more useful copolymers, containing both tere- and isophthalate units, are amorphous, clear, and easy to process. Polyarylates are used in automotive and appliance hardware and printed-circuit boards. Similar considerations in the copolymerization of iso- and terephthalates with 1,4-cyclohexanedimethanol or hexa-methylene diamine yield clear, amorphous, easy-to-process copolyesters or copolyamides,... 

Poly(para-phenylene) (PPP, 64) is insoluble and infusible and so films of PPP must be made by precursor routes (Scheme 6.19) [105]. The first of these, which was developed at ICI [106, 107], utilizes a radical polymerization of the diacetate 82 to produce a precursor polymer 83 that is thermally converted to PPP. This method produces PPP containing about 15% 1,2-linkages. A totally para-polymer can be made by the method of Grubbs involving the stereoregular nickel-catalyzed living polymerization of the bis(silyl ether) 84 to 85, and then its conversion to 83 [108-110],... 

VI. 1.2.1. pages 1-8 Materials based on poly (vinyl chloride) i.e. materials based on plasticised poly(vinyl chloride) for containers for human blood and blood components and for containers for aqueous solutions for intravenous infusion. (1989) Covered by VI.1.2. (1-7)... 

The formation of poly(amic acid), which is the first step in this synthesis, is a fast exothermic reaction which is generally carried out at room temperature or slightly above in a solvent for the polymer. Under these conditions the extent of imidization is negligible. In a typical process, the diamine is dissolved in dimethylformamide, dimethylacetamide or dimethyl sulphoxide and the dianhydride is added portion-wise with cooling. A viscous solution of the poly(amic acid) is formed. The poly(amic acid) contains a mixture of m- and p- diamide units as shown above. The second step in the preparation of the polyimide is cyclization of the poly(amic acid). Aromatic polyimides are usually insoluble and infusible and cannot therefore be fabricated either in solution or in the melt. It is thus necessary to convert the poly(amic acid) to the polyimide in that physical form in which the final polymer is desired. For example, in the preparation of film the poly(amic acid) solution is cast and then heated firstly to about 150°C and finally to 300°C. During imidization, water is formed and may cause scission of the polymer chains, particularly in the casting of thick film. The addition of acetic anhydride and pyridine (catalyst) to the poly(amic acid) solution results in the effective removal of water from the reaction system and prevents molecular weight reduction. 

The inherent insolubility and infusibility of polyacetylene coupled with its sensitivity to air imposes a barrier to the processibility of the polymer. As a result, considerable efforts have been directed toward obtaining polyacetylene from workable, easily processible polymers by means of polymer analogous transformations. In particular, the synthesis of polyacetylene from the dehydrohalogena-tion of poly(vinyl chloride) has attracted a lot of attention but the polymers prepared by this route generally possess relatively short conjugated segments and contain structural defects and cross-links [198,199],... 

As a further example, unsubstituted poly(p-phenylene) (PPP), which is an insoluble and infusible conjugated polymer will be considered. Based on this polymer, Wegner and co-workers prepared several different types of hairy rods (see Fig. 26c-f) [66, 175,176]. Poly(2,5-di-n-dodecyl-l,4-phenylene) contains two flexible alkyl tails at each aromatic ring (see Fig. 26c) [175]. Such... 

Figure 3. Plot of net weight gain (%) in 1/4" PMMA rod versus time elapsed after removal from the final treatment solution. Data is indicated for an infusion experi-ment in which PMMA is treated with a diluent solution containing 50%/50% water/poly(ethylene glycol) (above) and 100% water (below).

The most important resins available for use as adhesives in high temperature structural applications are Pis and polybenzimidazoles (PBIs), both of which are described later (see Sections 5.35 and 5.33). These resins are supplied as prepolymers containing open heterocyclic rings, which are soluble and fusible. At elevated temperatures, the prepolymers undergo condensation reactions leading to ring closure and the formation of insoluble and infusible cured resins [8]. Table 5.5 provides examples of performance properties of a poly-etherimide adhesive (Ultem is trademark of SABIC Corp). IP-600 stands for Thermid IP-600 for which the chemical formula is shown in Rgure 5.1. 

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