Polyamide thermoplastic elastomers

The thermoplastic elastomer polyamides have found use in conveyor and drive belts, ski and soccer shoe soles, computer keyboard pads, silent gears in audio and video recorders and cameras, and thin film for medical applications. 

Chem. Descrip. Zinc borate CAS 1332-07-6 EINECS/ELINCS 215-566-6 Uses Flame retardant, smoke suppressant for plastisols, coatings for cellulosics, textiles, and adhesives synergist in PVC and halogenated polyester formulations, and in elastomers, thermoplastic elastomers, polyamides, and polyolefins strong char promoter Properties Wh. free-flowing powd., nonhygroscopic 6 p avg. particle size 99.9% < 30 p sol. 0.5 g/100 ml water sp.gr. 2.50 bulk dens. 18.1 Ib/ff oil absorp. 39 ref. index 1.48 Zb -237 [Great Lakes]... 

Chem. Descrip. Zinc borate CAS 1332-07-6 EINECS/ELINCS 215-566-6 Uses Flame retardant, smoke suppressant for plastisols, coatings for textiles, adhesives synergist in PVC and halogenated polyester formulations, and in elastomers, thermoplastic elastomers, polyamides, and polyolefins strong char promoter... 

Hot-melt adhesives are 100% solids that, in the broadest sense, include all thermoplastic polymers. Polymers that are primarily used as hot-melt adhesives include ethylene-vinyl acetate copolymers (EVA), polyvinyl acetates (PVA), polyethylene (PE), amorphous polypropylene, block copolymers (thermoplastic elastomers), polyamides, and polyesters. The oldest hot-melt adhesive, which has been in use since early times, is sealing wax. In principle, glutins and glue jellies also may be regarded as hot-melt adhesives. However, modern hot-melt adhesives are primarily synthetic products. The simplest hot-melt adhesives are rosin-wax mixtures. But these products have limited strength and thermal stability. 

Polyamide 11 resistance to oils, hydraulic fluids, heating oil, and other fuels is excellent. Table 5.89 and Figure 5.335 left. Compared to polyester-based thermoplastic elastomers, polyamide 11 exhibits better mechanical properties as well as better dimensional stability because of its low moisture absorption. This is especially important for supply lines that transport these liquids. PA 11 also exhibits low permeability for fuels. 

Considerable amounts of EPM and EPDM are also used in blends with thermoplastics, eg, as impact modifier in quantities up to ca 25% wt/wt for polyamides, polystyrenes, and particularly polypropylene. The latter products are used in many exterior automotive appHcations such as bumpers and body panels. In blends with polypropylene, wherein the EPDM component may be increased to become the larger portion, a thermoplastic elastomer is obtained, provided the EPDM phase is vulcanked during the mixing with polypropylene (dynamic vulcani2ation) to suppress the flow of the EPDM phase and give the end product sufficient set. 

Among the polyurethane, polyester, and polyamide thermoplastic elastomers, those with polyether-based elastomer segments have better hydrolytic stabihty and low temperature flexibiUty, whereas polyester-based analogues are tougher and have the best oil resistance (43). Polycaprolactones and aUphatic polycarbonates, two special types of polyesters, are used to produce premium-grade polyurethanes (12). 

Table 6. Trade Names of Multiblock Thermoplastic Elastomers Based on Polyurethane/Elastomer, Polyether/Elastomer, and Polyamide/Elastomer Block Copolymers...

Although some of the polyamides described in Section 18.10 are somewhat rubbery, they have never achieved importance as rubbers. On the other hand, the past decade and a half has seen interest aroused in thermoplastic elastomers of the polyamide type which may be considered as polyamide analogues of the somewhat older and more fully established thermoplastic polyester rubbers. 

If polypropylene is too hard for the purpose envisaged, then the user should consider, progressively, polyethylene, ethylene-vinyl acetate and plasticised PVC. If more rubberiness is required, then a vulcanising rubber such as natural rubber or SBR or a thermoplastic polyolefin elastomer may be considered. If the material requires to be rubbery and oil and/or heat resistant, vulcanising rubbers such as the polychloroprenes, nitrile rubbers, acrylic rubbers or hydrin rubbers or a thermoplastic elastomer such as a thermoplastic polyester elastomer, thermoplastic polyurethane elastomer or thermoplastic polyamide elastomer may be considered. Where it is important that the elastomer remain rubbery at very low temperatures, then NR, SBR, BR or TPO rubbers may be considered where oil resistance is not a consideration. If, however, oil resistance is important, a polypropylene oxide or hydrin rubber may be preferred. Where a wide temperature service range is paramount, a silicone rubber may be indicated. The selection of rubbery materials has been dealt with by the author elsewhere. ... 

FIGURE S.1 Chemical structure of block copolymeric thermoplastic elastomers (TPEs) (a) styrenic, (b) COPE, (c) thermoplastic pol)oirethane, and (d) thermoplastic polyamide. 

Mehrabzadeh M. and Delfan N., Thermoplastic elastomers of butadiene-acrylonitrile copolymer and polyamide. VI. Dynamic crosslinking by different systems, J. Appl. Polym. Sci., 77, 2057, 2000. 

FIGURE 13.13 Schematic representation of thermoplastic elastomers obtained through reaction of maleated ethylene-propylene copolymer (EPM) with polyamide-6 (PA-6). 

HMX HMX HMX HMX HMX HMX HMX HMX HMX HMX HMX HMX HNS NTO NTO/HMX NTO/HMX NTO/HMX PETN PETN PETN PETN PETN PETN PETN PETN PETN PETN RDX RDX RDX RDX RDX RDX RDX RDX RDX RDX RDX RDX RDX TATB/HMX Cariflex (thermoplastic elastomer) Hydroxy-terminated polybutadiene (polyurethane) Hydroxy-terminated polyester Kraton (block copolymer of styrene and ethylene-butylene) Nylon (polyamide) Polyester resin-styrene Polyethylene Polyurethane Poly(vinyl) alcohol Poly(vinyl) butyral resin Teflon (polytetrafluoroethylene) Viton (fluoroelastomer) Teflon (polytetrafluoroethylene) Cariflex (block copolymer of butadiene-styrene) Cariflex (block copolymer of butadiene-styrene) Estane (polyester polyurethane copolymer) Hytemp (thermoplastic elastomer) Butyl rubber with acetyl tributylcitrate Epoxy resin-diethylenetriamine Kraton (block copolymer of styrene and ethylene-butylene) Latex with bis-(2-ethylhexyl adipate) Nylon (polyamide) Polyester and styrene copolymer Poly(ethyl acrylate) with dibutyl phthalate Silicone rubber Viton (fluoroelastomer) Teflon (polytetrafluoroethylene) Epoxy ether Exon (polychlorotrifluoroethylene/vinylidine chloride) Hydroxy-terminated polybutadiene (polyurethane) Kel-F (polychlorotrifluoroethylene) Nylon (polyamide) Nylon and aluminium Nitro-fluoroalkyl epoxides Polyacrylate and paraffin Polyamide resin Polyisobutylene/Teflon (polytetrafluoroethylene) Polyester Polystyrene Teflon (polytetrafluoroethylene) Kraton (block copolymer of styrene and ethylene-butylene)... 

Grilamid - ENGINEERING PLASTICS] (Vol 9) - [POLYAMIDES-PLASTICS] (Vol 19) - ELASTOMERS SYNTHETIC - THERMOPLASTIC ELASTOMERS] (Vol 9) - ELASTOMERS SYNTHETIC - THERMOPLASTICELASTOMERS] (Vol 9)... 

Pebax is a thermoplastic elastomer PA is an aliphatic polyamide hard block (e.g., nylon-6, nylon-12) and PEG is an amorphous polyether (polyethylene oxide (PEO) or polytetramethylene oxide (PTMO)) soft block (Scheme 4.2). 

The above thermal analysis studies demonstrated the enhanced thermal stability of POSS materials, and suggested that there is potential to improve the flammability properties of polymers when compounded with these macromers. In a typical example of their application as flame retardants, a U.S. patent39 described the use of preceramic materials, namely, polycarbosilanes (PCS), polysilanes (PS), polysilsesquioxane (PSS) resins, and POSS (structures are shown in Figure 8.6) to improve the flammability properties of thermoplastic polymers such as, polypropylene and thermoplastic elastomers such as Kraton (polystyrene-polybutadiene-polystyrene, SBS) and Pebax (polyether block-polyamide copolymer). 

Poly(ether-b-amide). In these particular thermoplastic elastomers the hard blocks consist of aliphatic polyamides, whereas the soft segments are formed of aliphatic polyethers. 

PEBA exhibit a two-phase (crystalline and amorphous) structure and can be classified as a flexible nylon. Physical, chemical, and thermal properties can be modified by appropriate combination of different amounts of polyamide and polyether blocks [149], Hydrophilic PEBAs can be prepared which can have specific applications in medical devices. Similarly to other thermoplastic elastomers, the poiyamide-based ones find applications in automotive components, sporting goods conveyor belting, adhesives, and coatings [150]. In recent years the world consumption was approximately 6400 tons per year with about 80% in Western Europe and the rest equally split between the United States and Japan [143],... 

Linear polysiloxanes having reactive terminal groups are often condensed with reactive orgaiuc polymers. For example, hydroxy-terminated siloxanes can be condensed with a carboxy-terminated polyester, as illustrated in equation (28). The resulting polymers behave as thermoplastic elastomers, having some of the desirable properties of both siloxanes and polyesters. Similar condensation reactions have been used to synthesize siloxane copolymers with polyamides, polyethers, polycarbonates, and so on. 

Thermoplastic elastomers are most commonly formulated from elastomeric polyurethane or block copolymers of polystyrene-elastomer, polyamide-elastomer, or polyether-elastomer bases. Thermoplastic elastomers are provided as a raw material in pelletized form for subsequent compounding. The internal domain structure that is required for thermoplastic-elastomeric performance has been established by specific considerations of blending and structural-chemical interactions. In compounding operations, specific temperature ranges are required to assure that phase separation does not occur in the TPE base polymer. 

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