摘要:
Provided are a composition for preparing expandable polypropylene carbonate and an expandable polypropylene carbonate prepared therefrom, and more particularly, to a composition for preparing expandable polypropylene carbonate capable of using supercritical carbon dioxide as a foaming agent and producing a foam having excellent moldability by using an appropriate foaming method. By using the composition according to the present invention, highly magnificated expandable polypropylene carbonate capable of having excellent thermal stability and dimensional stability can be prepared.
摘要:
Provided is a resin composition for a sheet to an eco-friendly poly(alkylene carbonate) resin composition containing a poly(alkylene carbonate) resin developed by efficiently utilizing carbon dioxide, which is a major contributor to global warming, as a main material, and including an strength controller, a flexibilizer and a filler. The present invention can solve problems related to environment harmfulness of the existing polyvinyl chloride resin products and have excellent flameproofing property and stretching property. In addition, the present invention can employ a calender processing method, which allows mass production and overcome a small production type extrusion processing method, which is regarded as the biggest disadvantage of thermoplastics emerging as alternatives for the existing polyvinyl chloride products.
摘要:
Provided are transition metal catalytic systems for preparing ethylene homopolymers or copolymers of ethylene with α-olefins. More specifically, provided are Group 4 transition metal catalysts, which is characterized in that the catalyst comprises around the Group 4 transition metal a cyclopentadiene derivative, and at least one aryloxide ligand(s) having a fluorenyl group or a derivative thereof (which is ready to be substituted at 9-position) that functions as an electron donor and serves to stabilize the catalytic system by surrounding an oxygen atom that links the ligand to the transition metal at ortho-position, and there is no cross-linkage between the ligands; catalytic systems comprising such transition metal catalyst and aluminoxane cocatalyst or boron compound cocatalyst; and processes for preparing ethylene homopolymers or copolymers of ethylene with α-olefins by using the same.
摘要:
Provided are a complex prepared from ammonium salt-containing ligands and having such an equilibrium structural formula that the metal center takes a negative charge of 2 or higher, and a method for preparing polycarbonate via copolymerization of an epoxide compound and carbon dioxide using the complex as a catalyst. When the complex is used as a catalyst for copolymerizing an epoxide compound and carbon dioxide, it shows high activity and high selectivity and provides high-molecular weight polycarbonate, and thus easily applicable to commercial processes. In addition, after forming polycarbonate via carbon dioxide/epoxide copolymerization using the complex as a catalyst, the catalyst may be separately recovered from the copolymer.