Aromatic-aliphatic polyamides

The three methyl groups, which account for about 11.5 and 10.5% of the weight, eliminate crystallinity completely, both for the adipic acid-based aliphatic polyamide and the terephthalic acid-based aromatic-aliphatic polyamide. 

Ballistreri, A., Garozzo, D., Giuffrida, M., Maravigna, P, and Montaudo, G., Thermal Decomposition Processes in Aromatic-Aliphatic Polyamides Investigated by Mass Spectrometry, /. Polym. Sci Polym. Chem. Ed, 25,1049, 1987. 

The polymerization reaction takes place in a homogeneous dimethylacetamide solution, with catalytic amounts of PdCl2(PPh3)2 and an HBr scavenger. The carbonylation polycondensation proceeds rapidly at 115 C and is almost complete in 1.5 hours. This reaction was also used to prepare many aromatic-aliphatic polyamides from corresponding aliphatic diamines with aromatic dibromides. 

Goyal and co-workers [10] in their Fourier-transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) investigation of the thermal stability of N-phenyl substituted aromatic-aliphatic and of aromatic amides derived from 4,4-dianilodiphenyl showed that the aromatic-aliphatic polyamides had glass transition temperatures in the range 76-116 °C, whilst the aromatic polyamides had transition temperatures of 207-255 °C. The polymers were thermally stable, and had decomposition temperatures in excess of 400 °C in air. 

Grilamid Polyamide-12, reinforced or not, PA-12 also blends with aromatic-aliphatic polyamides EMS-American Grilon... 

The superior properties of aramid materials were the reason why significant research effort has been devoted to their synthesis. In 1989 there were at least 100 different chemical compositions of aromatic and aromatic-aliphatic polyamides [5] and there are indications that the number has doubled until today. This fact led the U.S. Federal TVade Commission to adopt a definition for aramid designating fibers of the aromatic polyamide type in which at least 85% of the amide linkages are attached directly to two aromatic rings. The compounds corresponding to this definition that have reached commercial stage are only four (Scheme 8.1) poly(r vphenylene isophthalamide) (MPDI), poly(p-phenylene terephthalamide) (PPTA), copoly(p-phenylene-3,4-diphenyl ether terephthalamide) (ODA-PPTA), and poly[5-amino-2(p-aminophenyl) benzimidazole terephthalamide] (SVM).The process of commercialization of every compound has always been the result of a constant trade-off between properties, processability and price. 

S. Zulfiqar, Z. Ahmad, M. Ishaq, and M. I. Sarwar, Aromatic-aliphatic polyamide/montmorillonite clay nanocomposite materials Synthesis, nanostmcture and properties. Materials Science and Engineering A, 525 (2009), 30-36. 

Tg measurements have been performed on many other polymers and copolymers including phenol bark resins [71], PS [72-74], p-nitrobenzene substituted polymethacrylates [75], PC [76], polyimines [77], polyurethanes (PU) [78], Novolac resins [71], polyisoprene, polybutadiene, polychloroprene, nitrile rubber, ethylene-propylene-diene terpolymer and butyl rubber [79], bisphenol-A epoxy diacrylate-trimethylolpropane triacrylate [80], mono and dipolyphosphazenes [81], polyethylene glycol-polylactic acid entrapment polymers [82], polyether nitrile copolymers [83], polyacrylate-polyoxyethylene grafts [84], Novolak type thermosets [71], polyester carbonates [85], polyethylene naphthalene, 2,6, dicarboxylate [86], PET-polyethylene 2,6-naphthalone carboxylate blends [87], a-phenyl substituted aromatic-aliphatic polyamides [88], sodium acrylate-methyl methacrylate multiblock copolymers [89], telechelic sulfonate polyester ionomers [90], aromatic polyamides [91], polyimides [91], 4,4"-bis(4-oxyphenoxy)benzophenone diglycidyl ether - 3,4 epoxycyclohexyl methyl 3,4 epoxy cyclohexane carboxylate blends [92], PET [93], polyhydroxybutyrate [94], polyetherimides [95], macrocyclic aromatic disulfide oligomers [96], acrylics [97], PU urea elastomers [97], glass reinforced epoxy resin composites [98], PVOH [99], polymethyl methacrylate-N-phenyl maleimide, styrene copolymers [100], chiral... 

Although not strictly the subject matter of this book, work is briefly reviewed next on the application of non mass spectrometric Py-GC methods in the determination of polymer structure. This information is inclnded in the hope, when necessary, that chemists will be able to adapt these methods by including a mass spectrometric detailed information on polymer structure acrylates [63, 105-107], rubbers [63, 108-110], PVC [63,111-115], aliphatic polyhydrazides [116], polyoxamides [116], polyamides [117], polyether imides [118], methacrylamide [119], aromatic aliphatic polyamides [117], polyurethanes [120], chitin graft poly(2-methyl 2-oxazolone) [121, 122], polyxylyl sulfide [123-126], epoxy resins [127], polyethylene oxalate [128], polytetrafluoroethylene [129], polyvinylidene chloride [129], polyepichlorohydrin, fluorinated ethylene-propylene copolymer [129], polyvinyl fluoride [129], polyvinylidene [129], fluoride [129], SBR copolymer [129] and styrene-isoprene copolymer [130]. 

With DMA the effect of temperature on the modulus can be studied. By increasing the temperature from -150 to 300°C, one encounters several transitions in PA (Fig. 3.1). There is a transition at about —120°C, the y-transition, which is due to the mobilization of methylene units. There is also a transition at —30°C, which is present in wetted aliphatic PA this is due to non-H-bonded amide units and is termed the /J-transition. At about 50°C the glass Uansition (Tg) (a-transition) of the aliphatic polyamides PA-6 and PA-6,6 occurs. At this Uansition, the modulus is lowered considerably. For partially aromatic PA, the Tg occurs above 100°C. The last transition is the flow temperature, at which temperature the material melts the flow temperature and the melt temperature, as measured by DSC, correspond well. The modulus is a measure of dimensional stability and increases with crystallinity and filler content (Fig. 3.12). 

Mechanical properties. See also Dynamic mechanical analysis (DMA) of polyamides, 138 of polyester LCPs, 52 of polyurethanes, 242-244 of semicrystalline aromatic-aliphatic polyesters, 45 Mechanical recycling, 208 Medical applications, for polyurethanes, 207... 

Aliphatic iodine derivatives, 14 376 Aliphatic ketones, 14 563, 571, 581-585 reactions of, 16 331-332 Aliphatic monothiopolyesters, 23 739 Aliphatic nitration, 12 187 Aliphatic peroxyacids, 13 464 Aliphatic peroxycarboxylic acids, 18 463 Aliphatic phosphines, 19 60 Aliphatic polyamides (PA), 10 207-210 19 713, 739. See also Aromatic polyamides PA entries producers of, 10 210 properties of, 10 208, 209t Aliphatic polycarbonates, 24 703 preparation of, 19 798 Aliphatic polyketones (PK), 10 197 costs of, 10 222 properties of, 10 198t Aliphatic poly(monosulfide)s, 23 702-704 Aliphatic polyphosphonate dyes, 9 480 Aliphatic poly(polysulfide)s, 23 711 Aliphatic polysulfides, 23 734 Aliphatic polysulfoxides, 23 733 miscibility of, 23 735 Aliphatic polyurea preparation, carbonyl sulfide in, 23 625... 

Aromatic nitrations, 17 160-161 by-products of, 17 161 kinetics of, 17 162 Aromatic nitriles, 17 243 Aromatic nucleophilic displacement, polyimide synthesis via, 20 273 Aromatic phosphines, 19 60, 62 Aromatic poly(monosulfide ketone)s, 23 709 Aromatic poly(monosulfide)s, 23 706 Aromatic polyamide copolymers, laboratory synthesis of, 19 720 Aromatic polyamide fibers, 24 614 Aromatic polyamides, 10 210-212 19 713-738. See also Aliphatic polyamides (PA)... 

Crystalline polymers exhibit the following basic properties They are opaque as long as the size of the crystallites or spherulites, respectively, lies above the wavelength of light. Their solubility is restricted to few organic solvents at elevated temperature. The following crystalline polymers have attained technical importance as thermoplastic materials polyethylene, polypropylene, aliphatic polyamides, aliphatic/aromatic polyamides, aliphatic/aromatic polyesters, poly-oxymethylene, polytetrafluoroethylene, poly(phenylene sulfide), poly(arylene ether ketone)s. 

Likewise, the Tm values of aromatic polyamides (aramids) arc higher than those of the corresponding aliphatic polyamides (nylons). The Tm of monadic and dyadic nylons decreases as the number of methylene groups in the chain increases. Thus the Tm values decrease stepwise as the number of... 

In general, copolymers cross-link more readily than polyamide PA 66. Mechanical properties of polyamides are modified by irradiation, as seen by reduced tensile strength (50% loss when irradiated in air, 16% under vacuum). Aromatic polyamides retain strength better than aliphatic polyamides. ... 

The polyamide membranes prepared from aromatic diamines and aliphatic dichlorides, or from aliphatic diamines and aromatic dichlorides may be feasible for ultrafiltration as well as aliphatic polyamide membranes. Ohya 57) investigated the separation characteristics of asymmetric poly(xylyleneadipamide) (72) membrane under severe conditions of high temperature and high (or low) pH. 

Direct amidation is generally carried out in the melt, although it can be done in an inert solvent starting from the dry salt (46). Because most aliphatic polyamides melt in the range of 200—300°C and aromatic-containing polyamides at even higher temperatures, the reactants and products must be thermally stable to be polymerized via this method. 

Kevlar Fibers. Table IX shows results obtained with Kevlar 950 fibers. The crystallinity of this aromatic polyamide is only slightly higher than that for the aliphatic polyamide samples that we studied (Table VI). But in Kevlar, as for PET fibers, the disorder parameter k is smaller than in PA 66 fibers. Thermal treatment at 220°C for 1 hour in slack conditions does not substantially increase the average crystallinity of the Kevlar 950 fibers and produces more distortions. Consequently, we conclude that the behavior of this Aramid fiber during our annealing treatment is similar to PA 66 as far as crystallinity is concerned. Kevlar 950 is also similar to PET fiber with regard to the behavior of the disorder parameter. 

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