Kevlar Poly

Suzuki cross-coupling has found applications in the preparation of specialty polymers, too. Rigid rod polymers may have very useful properties (the well-known Kevlar, poly(p-phenyleneterephtalamide) belongs to this family, too) but they are typically difficult to synthetize, characterize and process. Such materials with good solubility in organic solvents [38] or in water [39] were obtained in the reactions of bifunctional starting compounds under conventional Suzuki conditions with [Pd(PPh3)4] and [Pd(TPPMS)3] catalysts, respectively (Scheme 6.15). 

Aromatic polyamides or aramids. The best known in the specialty fiber market are Nomex (poly-m-phenyleneisophthalamide) and Kevlar (poly-p-phenyleneterephthala-mide). 

Nylon 6T melts at 370 C, Nomex is practically flameproof. Kevlar, poly (p-phynyleneterephthalamide) represents a break-through in high modulus aromatic polyamide fibre and mainly used as reinforcement tyres, conveyers belt etc., PBI is... 

Other examples of well-established trade names are Kevlar (poly(paraphenylene terephthalamide)), Plexy-glass (sheets of poly(methyl methacrylate)). Teflon (poly(tetrafluoroethylene)), and Dacron (PET fiber). 

Kevlar Poly(p-phenylene terephthalamide) fibers, resins E. I. du Pont de Nemoirrs... 

As a result of their anisotropic nature and consequent processability to near extended chain solid state structures, Kevlar (poly(p-phenylene terephthalamide) and the aromatic thermotropic polyesters approach their theoretical tensile moduli rather closely. Their fibers calculate to about 1500 g/d and can be formed experimentally in a range of 1000-1400 g/d. 

Fig. 10.8 TGA as a screening method for fire-resistance fibers. Derivative weight is shown as a function of temperature curves, under air. Fibers are fire-resistant (FR) Rayon, FR cotton. Rayon, Nylon, Kevlar, poly(benzrmidazole), and Nomex.

Aromatic Polyamide-Rigid Rod "Kevlar" Poly(p-Phenylene Terephthalamide) Fibers... 

Poly(p-phenylene terephthalamide) Kevlar Poly(W-phenyl-2-hydroxytrimethylene amine) Poly(phenylquinoxaline-imide-amide)... 

More than 100 polymers, both synthetic and natural, have been successfully electrospun into nanofibers, mostly from polyma solutions, as any polymer may be electrospun into nanofibers, provided that the polymer molecular weight is sufficiently high and the solvent can be evaporated in the time during the jet transit period, over a distance between the spinneret and the collector. Standard polymers successfully electrospun into nanofibers include polyacrylonitrile (PAN), poly(ethylene oxide) (PEO), poly(ethylene terephthalate) (PET), polystyrene (PS), poly(vinyl chloride) (PVC), Nylon 6, PVA, poly(8-caprolactone), Kevlar (poly[p-phenylene terephthalamide]), poly(vinylidene fluoride) (PVDF), polybenzimidazole, polyurethanes (PUs), polycarbonates, polysulfones, poly(vinyl phenol) (PVP), and many others [36,37]. Electrospinning has also been used to produce nanofibers from natural biomacromolecules, including cellulose [either electrospun from cellulose acetate (CA) with subsequent hydrolysis or directly electrospun from cellulose solutions in Af,Af-dimethylacetamide with lithium chloride], collagen and gelatin, modified chitin, chitosan, and DNA. 

---