摘要:
Fast response, high contrast Ferroelectric Liquid Crystal (FLC) electro-optic devices in which the FLC retains a helical director structure stable to unwinding are provided. In particular, high contrast distorted helix FLC electro-optic devices including half-wave plates in the visible wavelength region are provided. The FLC cells of this invention incorporate chiral FLCs which exhibit a ferroelectric phase and a chiral nematic phase at temperatures above the ferroelectric phase. The natural helix pitch of the FLC in the ferroelectric phase is sufficiently tighter than the thickness of the FLC layer such that it is not surface-stabilized. The chiral nematic phase has a natural helix pitch sufficiently greater than the cell thickness to facilitate alignment of the FLC in the device to achieve high contrast.
摘要:
A phenolic compound is provided which can be described by the formula ##STR1## in which Ar is a C.sub.6-20 aromatic moiety, L is a cyclohexanenorbornane linking moiety, L' is a divalent cycloaliphatic moiety, and each of m and n is a number within the range of 0 to about 10. Such phenols include the product of the addition reaction of phenol with a cyclohexenenorbornene compound such as 5-(3-cyclohexen-1-yl)bicyclo[2.2.1]hept-2-ene.
摘要:
Optically active oxirane derivatives containing a mesogenic molecular unit are suitable as dopes in liquid-crystal mixtures. They give liquid-crystalline ferroelectric phases having short response times and electroclinic phases having large electroclinic coefficients. A further advantage is that they induce a helix of very small pitch, so that they are also suitable for helix compensation in LC mixtures.
摘要:
A curable resorcinol-based epoxy resin is disclosed having the general structural formula (I) ##STR1## wherein at least one of R.sub.1, R.sub.2, or R.sub.3 is selected from the group consisting of (a) the general structural formula (II) ##STR2## wherein R.sub.4 is selected from the group consisting of hydrogen and an alkyl group having 1 to about 4 carbon atoms, and (b) an allyl group.
摘要:
A novel fluorine-containing aromatic compound of the formula: ##STR1## wherein X is ##STR2## in which R.sub.f is a perfluoroalkyl group having 1 to 10 carbon atoms, R.sub.f ' is a perfluoroalkyl group having 1 to 12 carbon atoms, p is an integer of 1 to 3, q is an integer of 0 to 3, r is 0 or 1, s is an integer of 0 to 5 and t is an integer of 0 to 5,Y is X, a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or a fluoroalkyl group having 1 to 8 carbon atoms, andeach A is independently ##STR3## in which D is an amino, carboxyl, hydroxyl, methyl or haloformyl group, and n is an integer of 1 or 2, or ##STR4## can be used to derive various compounds, some of which are useful for preparing a fluorine-containing epoxy compound or polyimide with good properties.
摘要:
A naphthalene derivative of the following general formula (1) having at least one allyl or propenyl group is described. ##STR1## In the formula, each G represents a hydrogen atoms or ##STR2## R.sup.1 's independently represent a hydrogen atom, an allyl group or a propenyl group provided that at least one or R.sup.1 's is an allyl group or a propenyl group, and R.sup.2 's independently represent a hydrogen atom, an unsubstituted or substituted monovalent hydrocarbon group having from 1 to 6 carbon atoms, or a halogen atom. The derivative is useful for modifying curable resins or resin compositions to provide cured products which have a low water absorption, high strength and a high glass transition temperature. The derivative has good working properties and a good heat resistance.
摘要:
A modified epoxy resin or compound of the formula: ##STR1## wherein A is the backbone reside of a glycidyl ether epoxy resin with removal of the glycidyloxy groups; R.sup.1 and R.sup.2 are independently a hydrogen atom or C.sub.1 -C.sub.12 alkyl; R.sup.3 is a glycidyl group; and n is an integer of greater than 1. A method for producing the modified epoxy resin is also disclosed.
摘要:
Polyethers having improved barrier to oxygen are normally solid, thermoplastic polyethers having aromatic ether repeating units in their backbones and pendent hydroxyl moieties and pendent amido, N-substituted amido and/or hydroxyalkyl moieties. Such polyethers are prepared by reacting diglycidyl ethers of dihydric aromatic compounds such as the diglycidyl ether of bisphenol A with dihydric phenols having pendent amido, N-substituted amido and/or hydroxyalkyl moieties such as 2,2-bis(4-hydroxyphenyl)acetamide and 3,5-dihydroxybenzamide.
摘要:
Compositions comprising epoxy resins containing one or more rodlike mesogenic moieties per molecule are cured with polyamines containing one or more rodlike mesogenic moieties per molecule. These curable compositions can be oriented by the application of an electric field or magnetic field or drawing and/or shear flow prior to and/or during curing. The resultant cured products exhibit an improvement in one or more physical and/or mechanical and/or thermal properties as compared to a like epoxy resin system which does not contain any rodlike mesogenic moieties.
摘要:
An epoxide resin having the formula I: ##STR1## in which R.sup.1 to R.sup.4 are the same or different and each is hydrogen or C.sub.1 -C.sub.12 alkyl; R.sup.5 to R.sup.12 are the same or different and each is C.sub.1 -C.sub.12 alkyl or alkenyl or the glycidyl residue such that at least two R.sup.5 to R.sup.12 groups are glycidyl residues; and R.sup.13 to R.sup.20 are the same or different and are hydrogen, halogen C.sub.1 -C.sub.12 alkyl or alkenyl.