摘要:
Epoxy interpenetrating polymer networks having chemical bonds between the interpenetrating networks are prepared from a first and a second polymer network, at least one of which contains an EPRXE resin; a resin having two epoxide functionalities represented by E and a reactive pendant nonepoxide functionality X. The two resin networks are sequentially crosslinked followed by activation of the pendant functionality of the EPRXE resin to form internetwork chemical bonds between the two resin networks affording an epoxy resin with both increased strength and toughness. The invention is also directed to the process of making interpenetrating polymer networks.
摘要:
The present invention relates to novel compositions of matter comprising fullerenes and polymers, wherein the fullerenes are combined with the polymer in an amount sufficient to result in a change or modification in the viscoelastic properties of the resulting composition from that of the unmodified polymer typically within the range of from about 0.01 wt. % to about 85 wt. %. Also included in the present invention is the process for making the novel fullerene-polymer compositions and the products produced by the process disclosed therein. The novel compositions show changes in the viscoelastic properties in comparison to the unmodified polymer, and hence, have utility in any application in which the unmodified polymer may be used, but wherein the application would benefit from the resulting change in the viscoelastic properties.
摘要:
The present invention provides for microporous ceramic materials having a surface area in excess of 50 m.sup.2 /gm and an open microporous cell structure wherein the micropores have a mean width of less than 20 Angstroms and wherein said microporous structure comprises a volume of greater than about 0.015 cm.sup.3 /gm of the ceramic. The invention also provides for a preceramic composite intermediate composition comprising a mixture of a ceramic precursor and finely divided particles comprising a non-silicon containing ceramic, carbon, or an inorganic compound having a decomposition temperature in excess of 400.degree. C., whose pyrolysis product in inert atmosphere or in an ammonia atmosphere at temperatures of up to less than about 1100.degree. C. gives rise to the microporous ceramics of the invention. Also provided is a process for the preparation of the microporous ceramics of the invention involving pyrolysis of the ceramic intermediate under controlled conditions of heating up to temperatures of less than 1100.degree. C. to form a microporous ceramic product.
摘要:
The present invention provides for amorphous, nanoporous, catalytic metal-containing ceramic material having a surface area in excess of 70 m.sup.2 /gm and characterized by a high content of open microporous cell structure wherein the micropores have a mean width of less than 20 Angstroms and wherein said microporous structure comprises a volume of greater than about 0.03 cm.sup.3 /gm of the ceramic. The invention also provides for a preceramic composite intermediate composition comprising a mixture of a ceramic precursor and from about 0.5 up to about 65 wt % of an organometallic compound containing a metal of Group IB, II, III, IV, IV, V, VIB, VIIA or VIII of the Periodic Table, including rare earth metals, whose pyrolysis product in ammonia or an inert atmosphere at temperatures of up to less than about 1100.degree. C. gives rise to the nanoporous catalytic ceramics of the invention. Also provided is a process for the preparation of the nanoporous ceramics of the invention involving pyrolysis of the ceramic intermediate under controlled conditions of heating up to temperatures of less than about 1100.degree. C. to form a nanoporous ceramic product useful in catalytic and membrane separation processes.
摘要:
A composite having fibers of relatively high elastic modulus embedded in a matrix of relatively low elastic modulus is provided with an interphase of elastic modulus less than the matrix modulus and cohesive energy higher than the matrix cohesive energy. The resulting composite has enhanced strength and toughness.
摘要:
The present invention relates to a novel process for producing silicon and/or aluminum containing iron alloy product as well as the material produced from same in either sheet or bulk structure form for electromagnetic circuit application. The process entails modifying an iron feedstock containing less than about 2.5 wt % silicon, aluminum or a combination thereof. The process further consists of diffusion of silicon or silicon and aluminum or aluminum into an iron feedstock by a pack diffusion or a chemical vapor deposition method in which the iron feedstock is heated to a temperature at which diffusion occurs in the presence of a pack containing silicon and/or aluminum sources, a reducing agent, a catalyst, and a filler, or in the presence of a flowing gas stream containing a volatile silicon compound. The resulting iron alloy product, which has a silicon content in the range of 0.25%--7% silicon, and an aluminum content in the range of about 0%--4% aluminum, has favorable properties for motor and transformer applications.
摘要:
The present invention provides for microporous ceramic materials having a surface area in excess of 70 m.sup.2 /gm and an open microporous cell structure wherein the micropores have a mean width of less than 20 Angstroms and wherein said microporous structure comprises a volume of greater than about 0.03 cm.sup.3 /gm of the ceramic. The invention also provides for a preceramic composite intermediate composition comprising a mixture of a ceramic precursor and nanoscale size metallic particles, whose pyrolysis product in inert atmosphere or in an ammonia atmosphere at temperatures of up to less than about 1100.degree. C. gives rise to the microporous ceramics of the invention. Also provided is a process for the preparation of the microporous ceramics of the invention involving pyrolysis of the composite intermediate under controlled conditions of heating up to temperatures of less than about 1100.degree. C. to form a microporous ceramic product.
摘要:
A computer model calculates a critical aspect ratio for a discontinuous fiber composite having fibers dispersed in a matrix. The critical aspect ratio is a function of the elastic modulus and the cohesive energy of the fiber and the matrix. The composite incorporates physical features such as fiber shape features or additives in the fiber or matrix which adjust the elastic modulus and/or cohesive energy of the fiber, of the matrix or both to a value different than the corresponding value for unmodified fiber material or matrix material. These adjustments are selected so that the critical aspect ratio for the material including the modifications will be less than the corresponding critical aspect ratio for the material without the modifications. The resulting composite provides enhanced load sharing between fiber and matrix.
摘要:
A composite having fibers of relatively high elastic modulus embedded in a matrix of relatively low elastic modulus is provided with an interphase of elastic modulus less than the matrix modulus and cohesive energy higher than the matrix cohesive energy. The resulting composite has enhanced strength and toughness.
摘要:
A method for consolidating finely divided diamond particles to produce a substantially fully dense article having improved resistance to wear and cracking. Diamond particles are heated to an elevated temperature for compacting to form the fully dense article. The article is then held at an elevated temperature and time sufficient to rearrange and substantially reduce the dislocations in the article resulting during compacting to achieve a substantially strain-free state in the article. The article is then cooled to room temperature after which it may be given an improved leaching treatment to achieve superior thermal stability.