Abstract:
Novel compounds are provided that are useful as catalysts, particularly in the polymerization of addition polymerizable monomers such as olefinic or vinyl monomers. The compounds are multinuclear complexes of transition metals coordinated to at least one unsaturated nitrogenous ligand. Catalyst systems containing the novel compounds in combination with a catalyst activator are provided as well, as are methods of using the novel compounds in the preparation of polyolefins.
Abstract:
Novel compounds are provided which are useful as catalysts, particularly in the polymerization of addition polymerizable monomers such as olefinic or vinyl monomers. The compounds are complexes of a mid-transition metal coordinated to at least two ligands, at least one of which is an unsaturated nitrogenous ligand. Depending on ligand substitution, stereospecific catalysts can be provided, including isospecific catalysts and syndiospecific catalysts. Catalyst systems containing the novel compounds in combination with a catalyst activator are provided as well, as are methods of using the novel compounds in the preparation of polyolefins.
Abstract:
The present invention provides an anti-pathogenic air filtration medium comprising a fibrous substrate whose fibers are coated with coating comprising a polymer. The coating provides an environment that is destructive to airborne pathogens. In particular, the filter medium can be used in a building air handling system that both filters the air and eliminates pathogens. The filter medium also can be used to create a new bio-protective gas mask that not only offers protection against chemical warfare agents, but also provides protection against biological pathogens.
Abstract:
A reinforced wallboard core is prepared from a slurry comprising a mixture of β-calcium sulfate hemihydrate, a cellulose ether additive other than CMC and an amount of water that is sufficient to form a slurry and resulting in a wallboard density of less than 0.8 g/cc. The β-calcium sulfate hemihydrate is hydrated by the water forming a wallboard core reinforced by the cellulose ether additive. The cellulose ether, having a molecular weight of at least about 20,000 and a viscosity grade of at least about 100 cps, is selected to give the reinforced wallboard core improved nail pull resistance and greater flexural strength than unreinforced wallboard of the same density. The reinforced wallboard core may be used for reduced-paper wallboard and/or for lightweight wallboard, for example.
Abstract:
Construction materials containing surface modified reinforcements are used to fabricate composite structures. The composite structures comprise a matrix material and surface modified reinforcements, such as fibers and particulates. The surface modifier may be applied to a fiber surface using conventional sizing equipment and provides a durable film on the fiber. The surface modifier may be selected to have multifunctional properties, for example, increasing fiber pull-out strength, imparting bio-active properties, improving moisture resistance and other desirable properties to the composite structure.
Abstract:
Novel compounds are provided that are useful as catalysts, particularly in the polymerization of addition polymerizable monomers such as olefinic or vinyl monomers. The compounds are multinuclear complexes of transition metals coordinated to at least one unsaturated nitrogenous ligand. Catalyst systems containing the novel compounds in combination with a catalyst activator are provided as well, as are methods of using the novel compounds in the preparation of polyolefins.
Abstract:
A composite structure comprises an inorganic discrete phase, an organic matrix phase and an interfacial layer comprising both the inorganic and organic phases. In one process, the inorganic discrete phase is partially dissolved and the precipitated by a chemical reaction forming an interfacial layer having a finite thickness and transitioning from 100% inorganic to 100% organic.
Abstract:
An in situ ionic interaction between two additives, one a cationic strength enhancing additive and one an anionic crosslinking additive, is used to improve the mechanical properties of an article formed from a composite material. The composite has a discrete phase bound together with a film of the additives, such as gypsum crystals bound together by a film of substituted starch or cellulose ether.
Abstract:
A method is provided for the polymerization of olefins substituted with a functional group using a transition metal catalyst that, by virtue of one or more stabilizing groups incorporated within the catalyst structure, “fixes” the stereoconfiguration of each olefinic monomer relative to the transition metal complex during each successive reaction in the polymerization process. The invention substantially reduces the likelihood of olefin rearrangement at the active site of the catalyst during polymerization. In one particular embodiment, the functional group is a polar, electron-donating group and the stabilizing group is a Lewis acid substituent; examples of polymers that can be prepared with such a system include poly(vinyl acetate), poly(vinyl alcohol), and poly(vinyl ethers). Novel complexes and catalyst systems useful in the polymerization method are also provided.
Abstract:
A gypsum-based composite structure is prepared from a slurry comprising a mixture of calcium sulfate hemihydrate, a cellulose ether additive other than CMC and an amount of water that is sufficient to form a slurry. The calcium sulfate hemihydrate is hydrated by the water forming a wallboard core reinforced by the cellulose ether additive. The concentration, viscosity grade and degree of substitution of the cellulose ether are selected to give the composite improved nail pull resistance and greater flexural strength.