The invention relates to poly(oligo(ethylene glycol) methacrylate) microgels, to the process for preparing same and the uses thereof in various fields of application such as optics, electronics, pharmacy and cosmetics. These microgels have the advantage of being monodisperse, pH-responsive and temperature-responsive. They can carry magnetic nanoparticles or biologically active molecules. These microgels may also form transparent films, which have novel optical and electromechanical properties.

The present invention relates to an aromatic polycarbonate obtained via the melt transesterification of a diaryl carbonate, a bisphenol and an endcapping agent selected from paracumyl phenol, dicumyl phenol, p-tert-butyl phenol and mixtures of at least two of said endcapping agents, said polycarbonate having a melt volume rate of at least 20 cm.sup.3/10 min (ISO 1133, 300° C., 1.2 kg), a terminal hydroxyl group content of at most 800 ppm by weight, a Fries branching content of at most 1300 ppm by weight and a content of bulky end groups of at least 20 mol % defined as the sum of the mol % of end-groups based on said bisphenol and the mol % of end-groups based on said endcapping agent.

The invention relates to a process of preparing a glycolide product from methyl polyglycolate or its product. The process comprises depolymerizing the methyl polyglycolate or its product in the presence of a depolymerization agent to make a depolymerized product; repolymerizing the depolymerized product to make a glycolic acid oligomer; and pyrolyzing the repolymerized mixture to make a glycolide product. A rare earth metal catalyst may be used facilitate the depolymerization reaction. The glycolide pyrolysis conversion rate may be greater than 90%. Also provided are related glycolide product and the glycolic acid oligomer. The glycolic acid oligomer may have a weight average molecular weight of 4,000-80,000.

Oligomeric substances which contain one or more (meth)acryloyl functional groups as well as two or more amide functional groups are useful as components of compositions which may be cured using actinic irradiation to provide polymeric articles.

The invention provides polyurethane and polyisocyanurate foams and methods for the preparation thereof. More particularly, the invention relates to closed-celled, polyurethane and polyisocyanurate foams and methods for their preparation. The foams are characterized by a fine uniform cell structure and little or no foam collapse. The foams are produced with a polyol premix composition which comprises a combination of a hydrohaloolefin blowing agent, a polyol, a silicone surfactant, and a non-amine catalyst used alone or in combination with an amine catalyst.

An oligomer is formed by reacting a diacid monomer with (a) epoxy resin or (b) glycidyl methacrylate, wherein the diacid monomer has a chemical structure of ##STR00001##
wherein X is —O—, ##STR00002##
and each R.sup.1 is independently CH.sub.3, CH.sub.2F, CHF.sub.2, or CF.sub.3. A composition containing the oligomer can be cured to serve as a sealant of an optoelectronic device, and the sealant can be lifted off by a laser beam irradiation.

The invention provides polyurethane and polyisocyanurate foams and methods for the preparation thereof. More particularly, the invention relates to closed-celled, polyurethane and polyisocyanurate foams and methods for their preparation. The foams are characterized by a fine uniform cell structure and little or no foam collapse. The foams are produced with a polyol premix composition which comprises a combination of a hydrohaloolefin blowing agent, a polyol, a silicone surfactant, and a non-amine catalyst used alone or in combination with an amine catalyst.

(Meth)acrylate-functionalized oligomers having a) an oligomeric backbone comprised of first segments and second segments and b) (meth)acrylate-functionalized end groups are provided. Such oligomers are useful as components of curable compositions. The first segments, second segments and (meth)acrylate-functionalized end groups are linked together by linking moieties derived from a polyisocyanate. The first segments are residues of a first segment precursor containing a plurality of repeating units and a plurality of isocyanate-reactive functional groups and having a number average molecular weight of at least 250 daltons. The second segments are residues of a second segment precursor, different from the first segment precursor, containing a plurality of repeating units and a plurality of isocyanate-reactive functional groups and having a number average molecular weight of at least 250 daltons. The first segment and the second segment exhibit a Hansen Solubility Parameter Distance Relative Energy Difference of at least about 4 and not more than about 9.

A process to prepare a (iv) cyclic polyester oligomer composition includes a cyclic polyester oligomer having furanic units and two to five repeat units. The process includes (a) reacting a monomer composition including: (i) a bifunctional furan-derivative and (ii) a diol in an linear oligomerization step to produce a (iii) linear oligomer composition including a linear oligomer species, (b) reacting the (iii) linear oligomer composition in a distillation-assisted cyclization (DA-C) step to form a (iv) cyclic polyester oligomer composition and a (v) diol byproduct. The (v) diol byproduct is removed by evaporation in the distillation-assisted cyclization (DA-C) step.

Described herein are thermoset compositions and kits of compositions suitable for use in additive fabrication processes including high concentrations of urethane methacrylate oligomers having at least one polymerizable group, and a number average molecular weight from 750 to 4000 g/mol, an effective quantity of a monofunctional reactive diluent monomer, a defined concentration of a network building agent having a molecular weight that is lower than the urethane methacrylate oligomer, optionally a photoinitiator, and optionally, additives. Also disclosed are methods of creating three-dimensional parts via additive fabrication processes utilizing urethane methacrylate oligomer-centric compositions, wherein various exposure irradiances, cure temperatures, and oxygen content levels are prescribed, as well as the articles cured therefrom.