摘要:
Functional polyolefins containing a terminal functional group; the block copolymers that can be obtained from such polyolefins by reaction with polymers reactive with the functional groups and the precursors used for the preparation of the functionalized polyolefins, which are made of olefin polymers terminated at one end with ZnR groups where R is an alkyl or aryl radical with 1-10 carbon atoms.
摘要:
Process for the continuous manufacture of thermomoldable thermoplastic composite materials comprising feeding simultaneously on a conveyor belt a granulated thermoplastic polymer together with a reinforcement selected from natural, artificial and synthetic fibers, and compacting and heating under pressure the thus-obtained mixture.
摘要:
The present invention relates to copolyethers comprising copolymers of 7,oxa-bicyclo(2,2,1)heptane, and its alkyl-derivatives, with one or more single-ring or condensed-rings cycloaliphatic ethers, comprising the characteristic group; ##STR1## wherein R' is hydrogen and R" is H, a halogen, or an alkyl radical containing a small number of carbon atoms, and which may also be halogen-substituted.If the ether contains one ring only, it contains from 5 to 12 atoms in the ring, and if it contains a condensed-ring system, it contains a total number of from 10 to 18 atoms in the rings.Those copolyethers show a anisotropic behaviour in the molten state, and therefore have liquid-crystal properties.
摘要:
Thermotropic liquid-crystalline aromatic polyesters processable in the molten state, comprising units derived from at least one dicarboxylic aromatic acid and from mono- and di-substituted (1-phenyl-ethyl)-hydroquinones in admixture with hydroquinone, and/or hydroquinones substituted with halogen or alky, aryl or cycloalkyl groups.
摘要:
The biotechnological resolution by means of stereoselective enzymatic thio-transesterification of the racemic mixture of the optical isomers of the compounds of formula (I): ##STR1## wherein: R, R' and R", alike or different form one another, represent a linear alkyl group of from C.sub.1 to C.sub.4, in the presence of an alcohol and an enzyme capable of selectively causing the reaction of thio-transesterification of the (L)-isomer to take place, with the (D)-isomer remaining substantially unchanged, and being then separated by means of per se known techniques.
摘要:
Liquid-crystalline, thermotropic, aromatic polyesters processable in the molten state, comprising units derived from hydroquinones substituted with aryl, aralkyl and aroyl groups, and from phenoxy-hydroquinone.
摘要:
There is disclosed a process for the biotechnological resolution, by enzymatic esterification of the corresponding racemic mixture of the S(+) and R(-) optical isomers of the oxazolidinonic compounds having formula (I): ##STR1## wherein R represents a, linear or branched, C.sub.1 -C.sub.8 alkyl group, which process is characterized in that, the racemic 3-alkyl-5-hydroxymethyl-oxazolidin-2-one derivative of formula (I) is reacted with an esterifying compound, selected from esters having formula (III): ##STR2## wherein R represents a, linear or branched, C.sub.1 -C.sub.10 alkyl or alkenyl group and R" represents a linear or branched, C.sub.1 -C.sub.4 alkyl, alkenyl group, a haloalkyl (chlorine, bromine) group or a diacyl glycerolic group or from acids having formula (IV):R'"--COOH (IV)wherein R'" represents a, linear or branched, C.sub.1 -C.sub.20 alkyl or alkenyl group or from anhydrides having formula (V): ##STR3## wherein R.sup.IV represents a, linear or branched, C.sub.1 -C.sub.6 alkyl group, in the presence of an enzyme, immobilized on a porous carrier, capable of giving rise selectively to the esterification reaction of the R(-) isomer, while leaving the S(+) isomer substantially unchanged, which latter is then separated according to known techniques.
摘要:
Thermotropic liquid-crystalline aromatic polyesters of 4,4'-dihydroxy-diphenyl substituted with a halogen or with an alkyl, cycloalkyl, aryl, aralkyl, keto or ether radical.
摘要:
A process for the chlorination of the benzene rings of tricyclo 8.2.2.2 hexadeca 4,6,10,12,13,15 hexane (or (2,2)-paracyclophane) having the formula (I): ##STR1## by gaseous chlorine, by operating in the presence of at least one metal chloride as a catalyst, and at least one co-catalyst having the formula V:R--OH (V)whereinR=hydrocarbon or alkylcarboxylic radical with linear or branched chain, containing from 1 to 6 carbon atoms is taught.
摘要:
Polyacetylene having an apparent density at 20.degree. C. greater than 0.6 g/ccm and a surface area below 60 m.sup.2 /g is prepared by polymerizing gaseous acetylene in the presence of a catalytic system consisting of:(a) an oxygenized compound of Ti or V, containing at least one metal-oxygen bond;(b) an organometallic compound of aluminum containing at least one hetero-atom, of the formula: ##STR1## wherein: ##STR2## while R=a hydrocarbon radical with 1-18 carbon atoms, and where R'.dbd.R, or halogen or alcoxyl.