The synthesis and some properties of nylon 4,T

The synthesis of nylon 4,T from tetramethylenediamine and a terephthalic acid derivative was studied in a two step-process: prepolymerization, followed by postcondensation in the solid state (4 h, 290°C). The prepolymers were prepared by the nylon salt method, ester polymerization method, interfacial method, and a low temperature solution method. A maximum ηinh of 1.52 was obtained. From a solution in trifluoroacetic acid, films were cast and on these films we studied its IR spectrum, WAXS, and melting behavior with DSC. A boiled up sample had a double melting transition at 434 and 475°C and a ΔH0 of 130 J/g

Segmented block copolymers based on dimerized fatty acids and poly(butylene terephthalate)

Segmented block copolymers based on dimerized fatty acids and poly(butylene terephthalate) (PBT) have been synthesized in the melt. Branched C36, C44 and C70 dimerized fatty acids with a low degree of unsaturation were used. The fraction of PBT was varied from 50 to 100wt%. The resulting polymers were analysed with d.s.c. and d.m.a. The glass transition temperature (Tg) increased with increasing weight fraction of PBT. Tg decreased with increasing molecular mass of the dimerized fatty acid. The melting temperature increased with increasing weight fraction of PBT and increasing molecular mass of the dimerized fatty acid. The range of service temperatures of the thermoplastic elastomers can therefore be enlarged by using dimerized fatty acid with a high molecular mass. With increasing molecular mass of the dimerized fatty acid the storage modulus and the melting and crystallization enthalpy did not change significantly. The storage modulus can be described as a function of the volume fraction of crystalline PBT, but is not a function of the type of dimerized fatty acid

Impact modification of poly(caprolactam) by copolymerization with a low molecular weight polybutadiene

Caprolactam and a reactive, low molecular weight polybutadiene were polymerized in an autoclave, followed by post-condensation in the solid state. The rubber concentration was varied (0–30 wt%). The morphology of the reaction products was studied by transmission electron microscopy. In the materials with 10 and 20 wt% polybutadiene, large spherical polybutadiene-rich domains with nylon sub-inclusions were observed. The 30 wt% polybutadiene product was shown to have a co-continuous structure. The moduli of the materials decrease rapidly with rubber content and only the material with the highest polybutadiene content had a high notched Izod impact strength

Telechelic polyisobutylene with unsaturated end groups and with anhydride end groups

Anhydride terminated polyisobutylene (PIB) oligomers were synthesized in a one- or two-step process from chlorine terminated oligomers. In the one-step process, chlorine functional oligomers were just heated in the presence of maleic anhydride (MA) for 12 h at 190°C without a catalyst. In the two-step process, the chlorine end functional groups were first converted by selective dehydrochlorination to isopropenylpoly-isobutylene end groups with t-BuOK in refluxing tetrahydrofuran during 16 h. In a second step, MA was coupled to the PIB with unsaturated end groups by reacting the oligomer with MA for 12 h at 190°C. These reactions could be followed by i.r. and n.m.r. The PIB-MA obtained had a functionality between 30% and 100%. In order to study the formation of amine functionalities, the PIB-MA was reacted with diamines. The coupling gave an imide bonding

Impact behaviour of nylon-rubber blends: 4. Effect of the coupling agent, maleic anhydride

Blends of 90 wt% nylon-6 and 10 wt% EPDM (ethylene propylene diene monomer) rubber were prepared. The rubber was grafted with various amounts of maleic anhydride (MA) with the aid of a peroxide. The initial moduli and the melt viscosities of the rubbers were only a little affected by the MA and peroxide concentrations. The effect of MA concentration on the blending process and the impact behaviour was studied. The interfacial layer was investigated using infra-red spectroscopy and elemental analysis. The MA grafted onto the rubber was found to react with the nylon during the blending process. With the MA-grafted rubbers, a much finer dispersion could be obtained. However, the concentration of the coupling agent, within the range 0.13 to 0.89 wt% grafted onto the rubber, has hardly any influence on either the dispersion process or the impact behaviour of the blends

N,N'-(p-Phenylene)dibenzamide (PPDB)

C20N202H16, monoclinic, P2~/c, a = 18.065(1), b = 5.247(1), c = 8.027(1) A, fl = 93.99 (1) °, Z = 2. The crystal structure has been refined by least-squares techniques. R w = 7.3%. The structure contains planar phenyl rings which are\ud rotated with respect to the plane of the amide group owing to steric hindrance. The molecules are connected in one dimension by means of hydrogen bonds

Polyesteramides with mixtures of poly(tetramethylene oxide) and 1,5 pentanediol

Segmented polyesteramides have been synthesized from N,N¿-bis(p-carbomethoxybenzoy)butanediamine as crystalline segments and mixtures of poly(tetramethylene oxide) (mol. wt. 1000) and 1,5-pentanediol as soft segments. The polymerization was carried out in the melt at 250°C for 1 h while vacuum was applied. The melting behaviour of the copolymers was studied by differential scanning calorimetry. The mechanical properties were investigated on injection moulded bars, using dynamic mechanical analysis. It was found that the copolymers with more than 50% molar ratio pentanediol showed two glass transition temperatures and two melting temperatures. The glass transition temperatures were not affected by the composition. The melting temperatures increased with pentanediol content. The pentanediol seems in part to be present as adjacent re-entry groups. The under-cooling for these copolymers was very small, which means that these segmented copolymers crystallize very fast