摘要:
Copoly(imide oxetane) materials are disclosed that can exhibit a low surface energy while possessing the mechanical, thermal, chemical and optical properties associated with polyimides. The copoly(imide oxetane)s are prepared using a minor amount of fluorinated oxetane-derived oligomer with sufficient fluorine-containing segments of the copoly(imide oxetane)s migrate to the exterior surface of the polymeric material to yield low surface energies. Thus the coatings and articles of manufacture made with the copoly(imide oxetane)s of this invention are characterized as having an anisotropic fluorine composition. The low surface energies can be achieved with very low content of fluorinated oxetane-derived oligomer. The copolymers of this invention can enhance the viability of polyimides for many applications and may be acceptable where homopolyimide materials have been unacceptable.
摘要:
The present invention relates to a method for the production of a colored polyoxymethylene copolymer by mixing a raw polyoxymethylene copolymer in particulate form, comprising 2 to 30% by weight of unreacted residual monomers, with a coloring agent in particulate form, in a degassing apparatus. In addition, the present invention relates to the colored polyoxymethylene copolymer obtainable by the process and the use of the colored polyoxymethylene copolymer for the production of molding parts.
摘要:
A process for recycling polyoxymethylene polymers is disclosed. A polyoxymethylene polymer is at least partially dissolved in an aprotic compound. The resulting solution or suspension (liquid mixture) is then contacted with a catalyst which causes the polyoxymethylene polymer to be converted into a cyclic acetal. The cyclic acetal can be separated, collected and used in other processes. In one embodiment, the cyclic acetal may be used to produce a polyoxymethylene polymer.
摘要:
The present invention relates to a process for preparing polytetrahydrofuran, polytetrahydrofuran copolymer, diester or monoester by polymerizing tetrahydrofuran in the presence of at least one telogen and/or comonomer and of an acidic heterogeneous catalyst based on activated sheet silicates or mixed metal oxides in a fluidized bed.
摘要:
A polymer which can be crosslinked by high-energy radiation and contains from 0.1 to 50% by weight, based on the polymer, of 2,3-dihydrofuran groups or derivatives thereof, each calculated as 2,3-dihydrofuran.
摘要:
Process for producing coatings or moldings by radiation curing, which involves using high-energy light to irradiate radiation-curable compositions containing 1-100% by weight, based on the total amount of free-radically or cationically polymerizable compounds, of compounds A) containing at least one cationically polymerizable 2,3-dihydrofuran group.
摘要:
A process for producing a high-molecular-weight polydioxolane, which includes the steps of: polymerizing 1,3-dioxolane using a polymerization catalyst comprising a heteropolyacid and a ketone; and neutralizing the resulting polymerization reaction product using an organic amine and/or ammonia. A hydrophilic film, which includes a resin including a polydioxolane and having a particular molecular weight and has a particular crystallinity and a particular spherulite's size. A film crumbly in cold water is produced by forming a film under particular forming conditions from a resin including a polydioxolane and having a particular molecular weight, or by subjecting an already formed film to particular thermal hysteresis.
摘要:
Polyoxyalkylene glycol monoethers of monohydric alcohols are prepared by a process in which tetrahydrofuran or a mixture of tetrahydrofuran with a total of not more than 95 mol %, based on the amount of tetrahydrofuran used, of one or more comonomers from the group consisting of the cyclic ethers and acetals is polymerized in the absence of water and in the presence of a monohydric alcohol and of an anhydrous heteropoly acid catalyst.
摘要:
A process for polymerizing oxiranes, oxetanes, oxepanes, dioxolanes, trioxanes, and tetrahydrofurans to their respective polymers by contacting them with a selected metal compound is disclosed; and also a process for depolymerizing polytetrahydrofurans to monomeric tetrahydrofurans by contacting the polymer with a selected metal compound at a temperature of about 100.degree. C. to about 250.degree. C. The catalysts may be in solution of part of a heterogeneous solid, and selected organic compounds are used as accelerators in the polymerizations. The polymeric products, some of which are novel, may be used as polyether monomers for further polymerization, as by reaction with isocyanates to produce polyurethanes, and other useful polymers. Some of the polymeric products are relatively high in molecular weight and are suitable for direct use, for instance as spandex fibers.