摘要:
The present invention encompasses polyurethane compositions comprising aliphatic polycarbonate chains. In one aspect, the present invention encompasses polyurethane foams, thermoplastics and elastomers derived from aliphatic polycarbonate polyols and polyisocyanates wherein the polyol chains contain a primary repeating unit having a structure: In another aspect, the invention provides articles comprising the inventive foam and elastomer compositions as well as methods of making such compositions.
摘要:
The present disclosure describes polymer compositions comprising aliphatic polycarbonate chains containing epoxy functional groups. In certain embodiments, the aliphatic polycarbonate chains comprise epoxy functional groups capable of participating in epoxide ring-opening reactions. In certain embodiments, the invention encompasses composites formed by the reaction of nucleophilic reagents and epoxide functional groups, wherein the epoxide functional groups are located on aliphatic polycarbonate chains.
摘要:
In one aspect, the present invention provides catalysts for the carbonylation of heterocycles. The inventive catalysts feature metal-ligand complexes having cationic functional groups tethered to the ligand, wherein the tethered cationic groups are associated with anionic metal carbonyl species. The invention also provides methods of using the inventive catalysts to affect the ring opening carbonylation of epoxides.
摘要:
Continuous flow systems and methods produce succinic anhydride by a double carbonylation of ethylene oxide with carbon monoxide and at least one catalyst. In some embodiments, the double carbonylation occurs using a single catalyst. In other embodiments, a first catalyst is used to promote the first carbonylation, and a second catalyst different from the first catalyst is used to promote the second carbonylation. The succinic anhydride is isolated from the product stream by crystallization and the catalyst is recycled to the reaction stream.
摘要:
(Salph or methoxy salph) Co (initiating ligand) catalyze homopolymerizing rac-PO to produce pure highly isotactic PPO and rac-1-butylene oxide to produce pure isotactic poly(butylene oxide). A product is unfractionated isotactic PPO of m-dyad content >81%, normally at least 99%.
摘要:
Methods for opening a hard mask and a silicon-on-insulator substrate in a single process chamber are disclosed. In one embodiment, the method includes patterning a photoresist over a stack including an anti-reflective coating (ARC) layer, a silicon dioxide (SiO2) based hard mask layer, a silicon nitride pad layer, a silicon dioxide (SiO2) pad layer and the SOI substrate, wherein the SOI substrate includes a silicon-on-insulator layer and a buried silicon dioxide (SiO2) layer; and in a single process chamber: opening the ARC layer; etching the silicon dioxide (SiO2) based hard mask layer; etching the silicon nitride pad layer; etching the silicon dioxide (SiO2) pad layer; and etching the SOI substrate. Etching all layers in a single chamber reduces the turn-around-time, lowers the process cost, facilitates process control and/or improve a trench profile.
摘要:
Techniques for semiconductor processing are provided. In one aspect, a method for patterning one or more features in a semiconductor device comprises the following step. At least one critical dimension of the one or more features is reduced during etching of the antireflective material. A lithographic structure is also provided.
摘要:
The present invention encompasses polymer compositions comprising aliphatic polycarbonate chains containing functional groups that increase the polymer's ability to wet or adhere to inorganic materials. In certain embodiments, chain ends of the aliphatic polycarbonates are modified to introduce silicon-containing functional groups, boron-containing functional groups, phosphorous-containing functional groups, sulfonic acid groups or carboxylic acid groups.
摘要:
The present invention provides articles made from structurally precise poly(propylene carbonate) and blends thereof. Provided articles include articles manufactured from poly(propylene carbonate) wherein the PPC has a high head-to-tail ratio, low ether linkage content, narrow polydispersity and low cyclic carbonate content. Also provided are articles made from, incorporating or coated with structurally precise PPC.