摘要:
In a process for producing polytrimethylene terephthalate by esterification of terephthalic acid with 1,3-propanediol and polycondensation, the vapors formed are rectified, the liquid phase is recirculated to the process, and the lower-boiling components are condensed. To obtain an almost completely stripped condensate, it is provided to circulate the condensate and strip the same with air as well as to subject the exhaust air to a catalytic oxidation.
摘要:
Copolymers having linked internal polyether blocks and internal polyamide blocks have advantageous physical properties and solvent-gelling abilities. The copolymer may be prepared from a reaction mixture that contains 1,4-cyclohexane dicarboxylic acid (CHDA) and poly(alkyleneoxy) diamine (PAODA). Optionally, the reaction mixture contains no monofunctional compound reactive with either amine or carboxylic acid groups, however some of this monofunctional compound may be present. Dimer diamine and/or dimer acid may be present in the reaction mixture. A copolymer may also be prepared from a reaction mixture containing dimer acid and at least two diamine compound(s) including PAODA and short-chain aliphatic diamine having 2-6 carbons (SDA), wherein: a) the reaction mixture comprises x grams of PAODA and y grams of SDA, and x/(xnully) is 0.8-0.98; b) the reaction mixture weighs z grams, and x/z is at least 0.25; and c) the reaction mixture contains either no co-diacid, or comprises a small amount of co-diacid, wherein, if the reaction mixture comprises a small amount of co-diacid, then acid equivalents from co-diacid contribute less than 25% of the total acid equivalents present in the reaction mixture.
摘要:
The invention relates to a process for preparing stabilized compositions based on polyamide. The stabilizer is a phosphorus stabilizer selected from phosphorous acid and hypophosphorous acid. It is introduced before or during the polymerization of the polyamide. The use of these stabilizers prevents foaming phenomena.
摘要:
The thermal degradation of the biodegradable bacterial polyesters poly(3-hydroxybutyrate), PHB, and poly(3-hydroxybutyrate-co-3-hydroxyvalerate), PHB/V produces a macromer, especially a 1000-6000 g/mol macromolecule, which contains an unsaturated end group as well as a carboxylic acid end group. The macromers may be polymerized to produce homopolymers and copolymers for different applications in which amphiphilic and biocompatible properties are required, for example, drug delivery systems.
摘要:
Disclosed is a copolyester resin composed mainly of terephthalic acid, ethyleneglycol, 1,4-cyclohexanedimethanol, polyethyleneglycol bisphenol-A and a multifunctional monomer. According to the current invention, the multifunctional monomer and polyethyleneglycol bisphenol-A are additionally copolymerized along with 1,4-cyclohexanedimethanol, whereby the resultant copolyester resin can have low haze and high melt viscosity and melt strength, with superior moldability due to low melt pressure. In addition, extrusion blow molded articles and profile extruded articles, such as bottles and tubes, are provided by use of the copolyester resin having superior properties.
摘要:
A composition of matter, comparising: a chemically functionalized carboxylate-alumoxane that is functionalized with a chemically reactive substituent, and a reactive compound, wherein the chemically reactive substituent reacts with the reactive compound so as to link the carboxylate-alumoxnae to the reactive compound and form a polymer matrix. The functional groups on the carboxylate-alumoxane can vary depending on the desired properties of the matrix. Also, the composition of matter may comprise a cross-linked matrix in which the cross-linked components consist of functionalized alumoxanes.
摘要:
The present invention is directed to processes for the manufacture of multifilament yarn, including the steps of extruding multifilaments of a polymer containing at least mole 85 percent L-lactide and not more than 15 mole percent glycolide, spinning the extruded multifilaments to form a spun yarn, passing the spun multifilament yarn through an orientation roll heated at a temperature of less than 98null C. and drawing the spun multifilament yarn to a draw ratio of at least 4:1 to form an oriented multifilament fiber, annealing the oriented multifilament yarn at a temperature greater than that of the orientation roll, and redrawing the annealed, oriented multifilament yarn by at least 10 percent at a temperature lower than the temperature of annealing.
摘要:
Dendritic polymer conjugates which are useful drug delivery systems for carrying platinum containing anti-tumor agents to malignant tumors are prepared by obtaining a dendritic polymer having functional groups which are accessible to a platinum containing compound capable of interacting with the functional groups, contacting the dendritic polymer with the platinum containing compound, and reacting the dendritic polymer with the platinum containing compound. The dendritic polymer platinates may be administered intravenously, orally, parentally, subcutaneously or topically to an animal having a malignant tumor in an amount which is effective to inhibit growth of the malignant tumor. The dendritic polymer platinates exhibit high drug efficiency, high drug carrying capacity, good water solubility, good stability on storage, reduced toxicity, and improved anti-tumor activity in vivo.
摘要:
A polyesteramide copolymer having a glass transition temperature (Tg) of less than or equal to 0null C., contains at least one hard segment containing at least one amide bond, and at least one soft segment containing at least one ester bond. The soft segment is formed from at least one dimer fatty acid and/or dimer fatty diol and/or equivalent thereof. The copolymer is particularly suitable for use as a hot melt adhesive on low energy surfaces.
摘要:
Novel poly-o-hydroxyamides can be cyclized to give polybenzoxazoles which have a good diffusion barrier effect with respect to metals. The poly-o-hydroxyamides can be applied to a semiconductor substrate by customary techniques and converted into the polybenzoxazole in a simple manner by heating. This results in a good barrier layer with respect to diffusion of metals. This allows the diffusion barrier between conductor track and dielectric to be substantially dispensed.