摘要:
A process is disclosed for preparing a titanium catalyst component useful for homopolymerizing 1-alkenes and for copolymerizing 1-alkenes with each other and/or with ethylene, consisting essentially in grinding a titanium halide compound/electron-donor complex with a magnesium aluminum halide obtained by precipitation from an organic solvent.In the process the ground product is first washed with a washing liquid containing a solvent for the aluminum halide/electron-donor complex which forms during the grinding process and by preference at least one alcohol, the molar ratio between alcohol and titanium in the ground product ranging between 50:1 and 1:20, and then the washed product is exposed to a liquid titanium halide compound.With this procedure, it is possible to obtain a titanium component which imparts to the polymerization catalyst an excellent stereospecificity along with a very high activity, and with which it is possible to obtain polymers, e.g. polypropylene, with a very low halogen content, a very low titanium content, and an excellent powder morphology and bulk density.
摘要:
The invention relates to a coating composition comprising an antimicrobial hydrophilic copolymer consisting of a macromer and a comonomer, the use of said coating composition in medical applications and, in particular in a medical device and to a medical device comprising the coating composition, preferably selected from catheters, endoscopes, laryngoscopes, tubes for feeding or drainage or endotracheal use or oesophageal use. The coating composition can further comprise a hydrophilic polymer, a polyelectrolyte and a photo-initiator.
摘要:
The invention relates to a process for the preparation of a polymer composition, the process comprising a step of contacting a polymer that comprises carboxyl groups with a cyclic imino ether compound characterized in that the cyclic imino ether compound is a phenylene oxazine according to formula (I), in which formula R=an oxazine group according to formula (II) n=0, 1, 2, 3, 4 or 5 and that the polymer is contacted with said oxazine in an extruder at a temperature above 100° C.
摘要:
The invention relates to compositions containing 80-30 weight % of bismaleimide-compounds, 5-60 weight % maleimide-amide compounds and 1-10 weight % maleic anhydride derivative. The invention further relates to the preparation of such compositions and to homogeneous curable compositions comprising bismaleimide/maleimide-amide/maleic anhydride compositions according to the invention. The obtained copolymers show good chemical resistance and a high heat distortion temperature.
摘要:
The invention relates to a compound comprising a reaction product of (A) an isocyanate functional compound of which at least 40 wt. %, relative to the total amount of (A), has a molecular weight of at least about 500, and (B) a nitrogen-containing compound capable of reacting with said isocyanate functional compound (A). The reaction product has a molecular weight of less then about 20,000 and comprises an effective amount of groups that are able to form reversible intermolecular physical interactions such that a resulting compound shows polymeric mechanical properties at a temperature below a transition temperature. The nitrogen-containing compound is, for instance, melamine, urea, acetoguanamine, benzoguanamine, cyanamide, dicyanamide, thiourea, isocytosine, pyrimidone or aminopyridine. The supramolecular compound comprising a suitable amount of the reaction products exhibits a relatively high elongation at break.
摘要:
A process for production of a polyolefin-based composite material of high rigidity, containing a polyolefin and a layered clay, involves impregnating a layered, swellable clay which is interstratified with a tetraalkyl cation, with at least one polymerizable monomer and then mixing this impregnated clay with a polyolefin and a peroxide, at a temperature above the melting point of the polyolefin. A polyolefin-based composite material containing 98-50 wt. % of a polyolefin, 1-50 wt. % of another homo- or copolymer and 1-50 wt. % of a layered clay, wherein the ratio between the modulus of elasticity of the material and that of the initial polyolefin, at a temperature which is 30° C. below the melting temperature of the polyolefin, is higher than or equal to 1 has high rigidity.
摘要:
The invention relates to a process for preparing a high-molecular polyamide or polyester by melt-mixing polyamide or polyester having a lower molecular weight with a carbonyl bislactam having formula 1, in which n=an integer of between 3 and 15. With the process according to the invention a permanent increase in the molecular weight of a polyamide is obtained within 2 minutes, whereas this takes at least 10 minutes under comparable conditions using a bislactam according to the state of the art.
摘要:
The invention relates to a process for the preparation of an aromatic bisoxazoline in which, in a first step, an aromatic carboxylic acid or an ester hereof reacts with an alkanolamine, after which the hydroxyalkylamide obtained is in a second step converted into an aromatic bisoxazoline in the presence of a catalyst. The catalyst is phosphinic acid, a (C1-C26) alkyl phosphinic acid, a (C6-C20)aryl phosphinic acid or an ester or an anhydride derived from one of these acids.
摘要:
The invention relates to a process for the preparation of an N-alkyl or N-aryl carbamoyl derivative in which an amine is contacted with a carbonic acid derivative according to the general formula: where fragments X in the form of XH are a lactam, oxime, imide or triazole. In particular the invention relates to the preparation of a blocked isocyanate according to a process in which no isocyanate is used. The invention also relates to the use of the N-alkyl or N-aryl carbamoyl derivative prepared according to the process according to the invention in a coating.
摘要:
The invention relates to a thermoplastic propylene block copolymer comprising one or more substantially crystalline polypropylene blocks and one or more 1-alkene-propylene copolymer blocks, in at least one of which 1-alkene-propylene copolymer blocks diene units are present, and to a process for preparing such a propylene block copolymer.According to the invention, as diene, a cyclic hydrocarbon compound is used wherein at least one double bond forms part of a strained structure, particularly a polycyclic compound with 7 to 20 carbon atoms containing at least one 4- and/or 5-ring, with one or more double bonds in or to the ring.The invention offers the advantage that it is possible to prepare block copolymers which can otherwise not or hardly be made, while at the same time only a small quantity is formed of byproducts which are soluble in the dispersant.