摘要:
The invention relates to a process for preparing polymers, with a polydispersity optionally approaching the theoretical polydispersity and substituted by functional groups in .alpha.,.omega.-positions, via radical polymerization of radically polymerizable monomers and using one or more initiators. In compliance with this process the degree of polymerization is maintained at the desired value by continuous elevation of the temperature.In case of a given heat program, the process of the invention renders possible to increase the conversion in producing polymers without the deterioration of the polydispersity.
摘要:
The invention relates to new sorbents of cellulose basis capable of forming inclusion complexes, as well as to a process for the preparation thereof. The new sorbents according to the invention are cellulose derivatives containing structural units of the general formula (I), ##STR1## wherein Cell is a group derived by removing m hydroxy groups from the glucose unit of the cellulose chain,m is an integer of 1 to 3,CD is a group derived by removing one hydroxy group from the .alpha., .beta. or .gamma.-cyclodextrin molecule,n is an integer of 1 to 5, andp stands for 0 or 1, which may optionally vary even within a single chain.The cellulose derivatives according to the invention are substances of loose structure, with large specific surface area and good swelling properties, which can be applied for solving the most diverse adsorption tasks. Thus e.g. the substances can be applied for the preparation of smoke filters in cigarettes, waste water purification (de-poisoning) filters, inserts for removing solvent vapors, etc., furthermore for solving specific tasks of fractionation according to molecular dimensions.
摘要:
The present invention concerns new cyclodextrin-polyvinyl alcohol polymers capable of forming inclusion complexes. The preparation of said polymers by cross-linking a cyclodextrin, a mixture of cyclodextrins, or carbohydrate mixtures containing cyclodextrins in the presence of polyvinyl alcohol, polyvinyl acetate or a polyvinyl alcohol-polyvinyl acetate copolymer, with a polyfunctional coupling reactant capable of reacting with the cyclodextrins and with the polymers present is also within the scope of the invention.