摘要:
It has been discovered that improved polystyrene products may be obtained by polymerizing styrene in the presence of p-t-butyl styrene (TBS) and optionally at least one di-olefinic substituted aromatic compound, such as isopropenyl styrene, sec-butenyl styrene, m-isobutenyl styrene, p-diisopropenyl benzene, diallyl benzene, and/or diallyl phthalate. The resulting copolymers have a higher glass transition temperature (T g ), a higher molecular weight distribution (MWD), a higher Mz, and a lower melt flow index (MFI) as compared with a polymerized product made by an otherwise identical method except that TBS and/or the di-olefinic substituted aromatic compound are not used. These copolymers are also more highly branched as compared with a polymerized product made by an otherwise identical method in the absence of TBS and/or a di-olefinic substituted aromatic compound.
摘要:
The aim of the present invention is: radically polymerisable compositions which contain at least one monofunctional monomer with at least one difunctional monomer; resins which are obtainable by radical copolymerisation of said compositions; it being possible for the resins to be photochromic or not; articles, notably ophthalmic articles, which are constituted totally or in part of such resins; new monofunctional monomers.
摘要:
Described is a polymerizable organic composition comprising an aromatic monomer having at least two vinyl groups, e.g., divinyl benzene, a polythiol monomer having at least two thiol groups, e.g., pentaerythritol tetrakis(2-mercaptoacetate), and an anhydride monomer having at least one ethylenically unsaturated group, e.g., methacrylic anhydride. Polymerizable compositions according to the present invention, may optionally further comprise a polymerizable comonomer having at least two (meth)acryloyl groups, e.g., pentaerythritol tetrakis(acrylate). Polymerizates prepared from polymerizable organic compositions of the present invention have a refractive index of at least 1.57 and an Abbe number of at least 33. Also described are photochromic articles prepared from such compositions.
摘要:
There is provided a method for producing hydrogel microparticles with spherical shape and having a narrow-disperse or mono-disperse size distribution. At least one temporary crosslinker such as those of formula (I), (Ila)- (Ilf) and at least one permanent crosslinker comprising two or more vinyl groups, such as: divinylbenzene (DVB), ethylene glycol dimethacrylate (EGDMA),diethyleneglycol dimethacrylate (DEGDMA), Ν,Ν'-methylenebisacrylamide (MBA), oligo/poly ethyleneglycol dimethyacrylate, 1,4-butanediol dimethacrylate, and 1,6- hexanediol dimethacrylate are combined in an organic solvent havinga polarity suitable for a precipitation polymerization to occur. The precipitation polymerization is allowed to take place without the addition of surfactant and/or stabilizer and/or the formed microparticles comprise less than 1% surfactant and/or stabilizer. These microparticles may be further functionalized to obtain amine and carboxylic acid units by functionalizing the monomers of the temporary crosslinkers. The functionalized microparticles are used for cryopreserving cells or as a vaccine delivery platform.
摘要:
A polymer film obtainable by polymerising a composition comprising: (a) a compound Formula (I); wherein: R is C1-4-alkyl, NH2 or C6-12-aryl; and M+ is a cation; (b) a monomer comprising at least two polymerisable groups; and (c) a solvent. Also claimed are compositions and processes for making the polymer films.