摘要:
An isosorbide-containing polycarbonate composition is provided. The composition contains a polycarbonate having repeat units derived from isosorbide, a polycarbonate- property-modifying additive, and a pH stabilizer. When a solution containing 10 wt.% of the composition dissolved in dichloromethane is prepared the solution has a non-aqueous pH in a range of equal to or between 0.8 below and 0.5 above the pH of the dichloromethane.
摘要:
A method of increasing the branching and polydispersity of a polycarbonate includes the steps of: (a) including in the polycarbonate at least one species of an alkyl substituted monomer, and (b) treating the polycarbonate at an elevated temperature and for a sufficient time to increase the branching and polydispersity relative to an otherwise equivalent polycarbonate without alkyl substituents.
摘要:
Polycarbonates incorporating terminal carbonate groups derived from ester-substituted activated carbonates, for example terminal methyl salicyl carbonate (TMSC) derived from the use of BMSC as the activated carbonate in a transesterification process, have unfavorable properties with respect to color, hydrolytic stability and thermal stability, particularly when the polycarbonate containing such end groups is molded. The number of activated carbonate end groups formed during the melt transesterification formation of polycarbonate can be reduced, however, without sacrificing the benefits of using an activated diaryl carbonate, and without requiring a separate reaction or additional additives by reacting a dihydroxy compound with an activated diaryl carbonate in the presence of an esterification catalyst to produce a polycarbonate, wherein the molar ratio of activated diaryl carbonate to dihydroxy compound is less than 1 when expressed to at least three decimal places, for example 0.996 or less.
摘要:
A method of making polycarbonate includes the steps of forming polycarbonate by a melt transesterification method using an activated diaryl carbonate, and compounding the polycarbonate with a phosphorus-containing compound that has an abstractable proton or hydrolyzable group. The phosphorous-containing compound is compounded with the polycarbonate in an amount sufficient to result in an improvement in the color properties of the polycarbonate as compared to pellets formed from the same polycarbonate without addition of the phosphorus-containing compound.
摘要:
Disclosed herein is a foam that includes a polysiloxane block copolymer; the polysiloxane block copolymer including a first block that comprises a polysiloxane block and a second block that includes an organic polymer; the second block not containing a polysiloxane; the polysiloxane block being about 5 to about 45 repeat units; the foam having average pore sizes of less than or equal to about 100 nanometers.
摘要:
A multiwall sheet comprises a sheet, comprising walls, wherein the walls comprise a first wall; a second wall; and an outermost rib extending between the first wall and the second wall, wherein the first wall extends longitudinally past the outermost rib to a first wall end and wherein the second wall extends longitudinally past the outermost rib to a second wall end; and an end cap comprising a top wall having a top wall end, a bottom wall having a bottom wall end, and a connecting wall disposed between the top wall end and the bottom wall end; wherein the end cap is disposed over the first wall end and the second wall end and wherein the top wall and the bottom wall extend longitudinally along the first wall and the second wall past the outermost rib.
摘要:
A method for preparing a molded article includes the steps of (a) obtaining a polycarbonate resin and (b) molding the polycarbonate resin. The polycarbonate resin is made by a transesterification reaction using an activated diaryl carbonate such that the polycarbonate is susceptible to the formation of internal ester linkages (IEL). The method occurs with the proviso that the polycarbonate resin, the molding conditions or both are selected to control the amount of IEL formed during the molding process to a level of less than 0.4 mol%.