Synthesis, elastomer reactions

Pentenamer Ionomers. Unsaturated polypentenamer elastomers have been derivatized by post-synthesis reactions (72—74). Phosphonate, thioglycolate, sulfonate, and carboxylate derivatives have been prepared and converted into ionomers. 

Fig. 2.2. Prepolymer reaction sequence for elastomer synthesis (from AHport Janes, 1973).

This type of reaction has to be assumed to occur also in catalyst-free multiblock copolymers or even during the formation of the polyurethane segments in conventional or reaction-injection-moulding (RIM) elastomer synthesis. This has been demonstrated in an annealing experiment with a narrow fraction of a prepolymer obtained from the reaction of POTM-4 with MDI. 

In general, the preparation of ionomers is a straightforward procedure. The particular acid group of interest can be introduced onto the hydrocarbon backbone either by direct copolymerization or post-synthesis reaction. The following five important groups of ionomers illustrate the various methods of preparation. These ionomer families are ethylene-based materials, ionic elastomers, modified polystyrenes, perfluorinated resins and halato-telechelic polymers. 

The structural analysis of the samples PP ADMH = 2 1 obtained at 60 and 80°C in the absence of catalysts shows the formation of a branched structure at temperatures lower than those required for the formation of allophanate (120-140°C) and biuret (100°C) structures [1]. The ability of the ADMH to form hydrazinium cations leads to the assumption that the elastomer synthesis with the participation of ADMH involves formation of reactive centers of ionic nature, similarly to the Ritter reaction, where the synthesis of the N-substituted amides of carboxylic acids passes through a stage of carbonium ion formation... 

Polyurethane adhesives can be produced from polyurethane elastomer waste by the application of glycolysis [72,73]. In the process of adhesive manufacturing, both the upper layer of the post-reaction mixture (mainly consisting of polyols appropriate for the elastomer synthesis) and the bottom layer (consisting of ethylene glycol, ethanolamines and their derivatives, as well as the remaining compounds useful in the elastomer synthesis) were utilized. The obtained adhesives were characterized by good mechanical properties. 

Chapter 12 discusses the use of the various monomers obtained from a petroleum origin for producing commercial polymers. Not only does it cover the chemical reactions involved in the synthesis of these polymers, but it also presents their chemical, physical and mechanical properties. These properties are well related to the applicability of a polymer as a plastic, an elastomer, or as a fiber. 

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. 

ADMET is quite possibly the most flexible transition-metal-catalyzed polymerization route known to date. With the introduction of new, functionality-tolerant robust catalysts, the primary limitation of this chemistry involves the synthesis and cost of the diene monomer that is used. ADMET gives the chemist a powerful tool for the synthesis of polymers not easily accessible via other means, and in this chapter, we designate the key elements of ADMET. We detail the synthetic techniques required to perform this reaction and discuss the wide range of properties observed from the variety of polymers that can be synthesized. For example, branched and functionalized polymers produced by this route provide excellent models (after quantitative hydrogenation) for the study of many large-volume commercial copolymers, and the synthesis of reactive carbosilane polymers provides a flexible route to solvent-resistant elastomers with variable properties. Telechelic oligomers can also be made which offer an excellent means for polymer modification or incorporation into block copolymers. All of these examples illustrate the versatility of ADMET. 

Phthalazinone, 355 synthesis of, 356 Phthalic anhydride, 101 Phthalic anhydride-glycerol reaction, 19 Physical properties. See also Barrier properties Dielectric properties Mechanical properties Molecular weight Optical properties Structure-property relationships Thermal properties of aliphatic polyesters, 40-44 of aromatic-aliphatic polyesters, 44-47 of aromatic polyesters, 47-53 of aromatic polymers, 273-274 of epoxy-phenol networks, 413-416 molecular weight and, 3 of PBT, PEN, and PTT, 44-46 of polyester-ether thermoplastic elastomers, 54 of polyesters, 32-60 of polyimides, 273-287 of polymers, 3... 

The synthesis of elastomers by step, chain, and ring-opening polymerizations is reviewed. These reactions are characterized as to the process variables which must be controlled to achieve the synthesis and crosslinking of an elastomer of the required structure. Both radical and ionic chain polymerizations are discussed as well as the structural variations possible through copolymerization and s tereoregularity. 

Uses Synthetic rubbers and elastomers (styrene-butadiene, polybutadiene, neoprene) organic synthesis (Diels-Alder reactions) latex paints resins chemical intermediate. 

Gheneim R, Perez-Beramen C, Gandini A. Diels-Alder reactions with novel polymeric dienes and dienophiles synthesis of reversibly cross-linked elastomers. Macromolecules 2002 35 7246-7253. 

---