摘要:
The present invention provides an irradiated crosslinked polyethylene containing reduced free radicals, preferably containing substantially no residual free radical. Disclosed is a process of making irradiated crosslinked polyethylene by irradiating the polyethylene in contact with a sensitizing environment at an elevated temperature that is below the melting point, in order to reduce the concentration of residual free radicals to an undetectable level. A process of making irradiated crosslinked polyethylene composition having reduced free radical content, preferably containing substantially no residual free radicals, by mechanically deforming the polyethylene at a temperature that is below the melting point of the polyethylene, optionally in a sensitizing environment, is also disclosed herein.
摘要:
The invention is the method of preparing macromer for use in making ophthalmic lenses comprising combining two or more monomers and using a macromer-forming catalyst, wherein the macromer-forming catalyst comprises triethylamine or bismuth.
摘要:
A stabilized adhesive composition is provided including one or more polymerizable cyanoacrylate monomers, a first free radical stabilizer in a stabilization effective amount, and a second free radical stabilizer in a stabilization effective amount. The free radical stabilizers are selected to minimize mutagenicity in the composition and are used in amounts which provide adequate stabilization for long term storage while reducing disadvantageous effects of the free radical stabilizers. The stabilized adhesive composition further may include a first anionic stabilizer comprising a vapor phase anionic stabilizer and a second anionic stabilizer comprising a liquid phase anionic stabilizer. The stabilized adhesive composition may also include or be used with a polymerization initiator. Methods for the application of the stabilized adhesive compositions to living tissue are also provided.
摘要:
The invention relates to a latex that may be utilized as a binder for nonwoven applications to form a permeable sublayer of personal hygiene articles. The latex is prepared by a process including the steps of (1) polymerizing a monomer mixture comprising styrene, itaconic acid, surfactant and water soluble free radical initiator to form a seed; (2) sequentially adding equal increments of a monomer mixture of styrene, butadiene and acrylic acid to the seed under emulsion polymerization conditions to form a styrene-butadiene-acrylic acid copolymer; and then (3) neutralizing the styrene-butadiene-acrylic acid copolymer to a pH of about 4.5 to 7 to form the latex.
摘要:
Disclosed is a method of preparing terminally functionalized telechelic polymers using a cationic living polymer product or a terminal tert-chloride chain end of a carbocationic quasiliving polymer product, which comprises quenching the polymer product with an N-substituted pyrrole to thereby functionalize the N-substituted pyrrole at the terminal reactive polymer chain end(s). Also disclosed are the terminal functionalized polyisobuyl N-substituted pyrrole compounds where the polyisobutyl group is substituted at the 2 and 3 position of the N-substituted pyrrole.
摘要:
A liquid-phase process for polymerizing α-olefins of the formula CH2═CHR, where R is H or an alkyl radical C1-C6, to produce a polymer that is soluble in the reaction medium, comprising the steps of: a) continuously polymerizing in liquid phase the α-olefin in the presence of a catalyst system based on a transition metal compound; b) continuously withdrawing from step a) a solution of polymer in the liquid reaction medium; c) mixing in one or more mixing stages said solution of polymer in the reaction medium with an organic deactivator having: at least a hydroxy group, a boiling point higher than 150° C., and a ratio between the molecular weight (MW) and the number of hydroxy groups (OH) comprised between 20 and 100.
摘要:
Disclosed is the observation that 7-aryl-quinone methides and 4-tert-butylcatechol, when used in combination in a vinyl aromatic monomer to inhibit polymerization,do not inhibit polymerization to the same extend as each would if used separately. Stated another way, a phenomenon has been observed that when these two compounds are used together, they can, to a large extent, render each other unable to inhibit polymerization in a vinyl aromatic monomer. Also disclosed are methods of preventing adverse results of this interaction when undesired and a method of using this interaction to prepare a reactive vinyl aromatic monomer having a concentration of 4-tert-butylcatechol that would otherwise inhibit polymerization. The invention is disclosed to be useful with the production and storage of any vinyl aromatic monomer and is disclosed to be particularly useful with the production and storage of styrene monomer.
摘要:
.alpha., .omega.-polymethacrylate glycols of the general formula ##STR1## are prepared and a method for their synthesis and their use as only or partial glycol component for the preparation of polyesters and polyurethanes and for the modification of alkyd and epoxide resins are described.
摘要:
A functionalized polymer comprising a polymer having at least one cyclic amine end group defined according to formula (I) ##STR1## where Z is an anionically-polymerized polymer; R.sub.1 is selected from the group consisting of organic groups containing from 1 to about 12 carbon atoms and a bridging bond; each R.sub.2 is independently selected from the group consisting of hydrogen, organic groups containing from 1 to about 12 carbon atoms, and a bridging bond; each R.sub.3 is independently selected from the group consisting of hydrogen and organic groups containing from 1 to about 12 carbon atoms; a is an integer from 4 to about 16; and b is an integer from 0 to about 12; and optionally including a bridge, formed by the selection of two of said bridging bonds, the bridge having 0 to about 6 carbon atoms between the bridging ring members.
摘要:
Toughened vinyl aromatic compounds, in particular high impact polystyrene, are prepared by a continuous process in which the vinyl aromatic compound and the impact modifier, an elastomeric block copolymer, are each prepared separately in a reaction zone by anionic polymerization, with or without heat exchange with the environment and, if required, with the addition of a solvent, and are polymerized until complete conversion is achieved, and the living chain ends are terminated in a manner known per se, and a thermoplastic, toughened molding material is based on a vinyl aromatic compound having a residual content of less than 50 ppm of monomers and less than 100 ppm of oligomers.