Polyamide, blends with

Meyer RV, Dhein R, Fahnler F (1979) Polyamide blends with high impact strength, DE Patent 2 734693... 

Afterfixing agent for improving the wet fastness properties of polyamide fibres dyed or printed with acid dyes. The light colour of this compound results in minimal effect on bright shades or white grounds of printed fabrics. Used to reserve polyamide when dyeing cotton/polyamide blends with direct dyes. 

REMOL ASN liquid has an excellent dispersing and compatibil-izing action in one-bath dyeing of wool or polyamide blends with acrylic fibers using anionic and cationic dyes and in dyeing polyester/acrylic fibers with disperse and cationic dyes. 

Polyethylene-Polyamide Blends with Compatibilizing Agents... 

Unstable friction of PA is attributed to tribo-oxidation processes, namely processes with formation of peroxide groups at a-carbon atoms. As a result, a branched and partially cross-linked secondary structure is formed on the friction surface. A 3D rigid skeleton formed in materials on the base of polyamide blends with thermosetting pol3miers (phenol, melaminoformalde-hyde, epoxy-novolac block copol3miers and other t3rpes) improves the wear resistance of their compositions compared to PA [102]. 

Equation 19.6 Graft-coupling reactions in polyamide blends with a mixture of epoxy and carboxy functional elastomer blends... 

More recently, a polyarylate-polyamide blend with improved chemical, stress-crack resistance is commercially offered (AX1500, Unitika). Due to the inherent immiscibUity of polyarylate with polyamide, the blend is opacpie and the notched Izod impact is somewhat sacrificed (Table 19.36). Compatibihty in polyarylate-PA6 blends could be achieved through addition of < 10 % of a reactive ethylene copolymer such as ethylene-glycidyl methacrylate copolymer (Okamoto et al. 1989). 

Fig. 5 a Scanning elecfxon microscope SEM) micrographs of polypropylene -polyamide blends without RS (broken under liquid nitrogen), b S EM micrographs of polypropylene polyamide blends with RS (broken under liquid nitrogen)... 

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. 

Multiblock Copolymers. Replacement of conventional vulcanized mbber is the main appHcation for the polar polyurethane, polyester, and polyamide block copolymers. Like styrenic block copolymers, they can be molded or extmded using equipment designed for processing thermoplastics. Melt temperatures during processing are between 175 and 225°C, and predrying is requited scrap is reusable. They are mostiy used as essentially pure materials, although some work on blends with various thermoplastics such as plasticized and unplasticized PVC and also ABS and polycarbonate (14,18,67—69) has been reported. Plasticizers intended for use with PVC have also been blended with polyester block copolymers (67). 

There has also been some interest in melt blending with polyamides to increase the toughness but at some sacrifice to dimensional stability and moisture resistance. 

Polyarylates can be blended with a wide range of commercially available thermoplastics, including polyamides, polycarbonates, polyetherketones, polyesters, and poly(phenylene sulfide), thus broadening their application domain. 

PESA can be blended with various thermoplastics to alter or enhance their basic characteristics. Depending on the nature of thermoplastic, whether it is compatible with the polyamide block or with the soft ether or ester segments, the product is hard, nontacky or sticky, soft, and flexible. A small amount of PESA can be blended to engineering thermoplastics, e.g., polyethylene terepthalate (PET), polybutylene terepthalate (PBT), polypropylene oxide (PPO), polyphenylene sulfide (PPS), or poly-ether amide (PEI) for impact modification of the thermoplastic, whereas small amount of thermoplastic, e.g., nylon or PBT, can increase the hardness and flex modulus of PESA or PEE A [247]. 

Properties of Maleated Ethylene-Propylene Copolymer (EPM) Blended with Polyamide-6 (PA-6)... 

Essentially nonionic soil-release agents comprise polyesters, polyamides, polyurethanes, polyepoxides and polyacetals. These have been used mainly on polyester and polyester/ cellulosic fabrics, either crosslinked to effect insolubilisation (if necessary) or by surface adsorption at relatively low temperature. Polyester soil-release finishes have been most important, particularly for polyester fibres and their blends with cellulosic fibres. These finishes, however, have much lower relative molecular mass (1000 to 100 000) than polyester fibres and hence contain a greater proportion of hydrophilic hydroxy groups. They have been particularly useful for application in laundering processes. These essentially nonionic polymers may be given anionic character by copolymerising with, for example, the carboxylated polymers mentioned earlier these hybrid types are generally applied with durable press finishes. 

Many efforts have been directed to finding methods that could reduce the HDPE permeability. One of them is HDPE blending with polymers such as polyamide (PA) or PVA with low permeability for hydrocarbons. To overcome the incompatibility between the nonpolar and polar polymers, a compatibilizer has to be present in these blends. 

Meincke O, Kaempfer D, Weickmann H, Friedrich C, Vathauer M, Warth H (2004). Mechanical properties and electrical conductivity of carbon-nanotube filled polyamide-6 and its blends with acrylonitrile/butadiene/styrene. Polymer 45 739-748. 

Polycarbonate is blended with a number of polymers including PET, PBT, acrylonitrile-butadiene-styrene terpolymer (ABS) rubber, and styrene-maleic anhydride (SMA) copolymer. The blends have lower costs compared to polycarbonate and, in addition, show some property improvement. PET and PBT impart better chemical resistance and processability, ABS imparts improved processability, and SMA imparts better retention of properties on aging at high temperature. Poly(phenylene oxide) blended with high-impact polystyrene (HIPS) (polybutadiene-gra/f-polystyrene) has improved toughness and processability. The impact strength of polyamides is improved by blending with an ethylene copolymer or ABS rubber. 

High-impact polystyrene (HIPS) is produced by polymerizing styrene in the presence of a rubber, usually poly(l,3-butadiene). HIPS has improved impact resistance compared to polystyrene and competes with ABS products at low-cost end applications such as fast-food cups, lids, takeout containers, toys, kitchen appliances, and personal-care product containers. HIPS as well as ABS and SMA are used in physical blends with other polymers, such as polycarbonates, polyesters, and polyamides, to improve impact resistance (Sec. 2-13c-3). 

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