摘要:
The benefits of liquid crystal polymers and polyetherimides are combined in an all-aromatic thermoplastic liquid crystalline polyetherimide. Because of the unique molecular structure, all-aromatic thermotropic liquid crystal polymers exhibit outstanding processing properties, excellent barrier properties, low solubilities and low coefficients of thermal expansion in the processing direction. These characteristics are combined with the strength, thermal, and radiation stability of polyetherimides.
摘要:
The benefits of liquid crystal polymers and polyetherimides are combined in an all-aromatic thermoplastic liquid crystalline polyetherimide. Because of the unique molecular structure, all-aromatic thermotropic liquid crystal polymers exhibit outstanding processing properties, excellent barrier properties, low solubilities and low coefficients of thermal expansion in the processing direction. These characteristics are combined with the strength, thermal, and radiation stability of polyetherimides.
摘要:
Main chain thermotropic liquid crystal esters, ester-imides, and ester-amides were prepared from AA, BB, and AB type monomeric materials and end-capped with phenylacetylene, phenylmaleimide, or nadimide reactive end-groups. The end-capped liquid crystal oligomers are thermotropic and have, preferably, molecular weights in the range of approximately 1000-15,000 grams per mole. The end-capped liquid crystal oligomers have broad liquid crystalline melting ranges and exhibit high melt stability and very low melt viscosities at accessible temperatures. The end-capped liquid crystal oligomers are stable for up to an hour in the melt phase. They are highly processable by a variety of melt process shape forming and blending techniques. Once processed and shaped, the end-capped liquid crystal oligomers were heated to further polymerize and form liquid crystalline thermosets (LCT). The fully cured products are rubbers above their glass transition temperatures.
摘要:
A mechanically undensified aromatic polyimide foam is made from an aromatic polyimide precursor solid residuum and has the following combination of properties: a density according to ASTM D-3574A of about 0.5 pounds/ft.sup.3 to about 20 pounds/ft.sup.3 ; a compression strength according to ASTM D-3574C of about 1.5 psi to about 1500 psi; and a limiting oxygen index according to ASTM D-2863 of about 35% oxygen to about 75% oxygen at atmospheric pressure. The aromatic polyimide foam has no appreciable solid inorganic contaminants which are residues of inorganic blowing agents. The aromatic polyimide which constitutes the aromatic polyimide foam has a glass transition temperature (Tg) by differential scanning calorimetry of about 235.degree. C. to about 400.degree. C.; and a thermal stability of 0 to about 1% weight loss at 204.degree. C. as determined by thermogravimetric analysis (TGA).The aromatic polyimide foam has utility as foam insulation and as structural foam, for example, for aeronautical, aerospace and maritime applications.
摘要翻译:机械不透明的芳族聚酰亚胺泡沫由芳族聚酰亚胺前体固体残渣制成,具有以下特性组合:根据ASTM D-3574A的密度为约0.5磅/ ft 3至约20磅/ ft 3; 根据ASTM D-3574C的约1.5psi至约1500psi的压缩强度; 和根据ASTM D-2863的约35%氧气至约75%氧气的极限氧气指数。 芳族聚酰亚胺泡沫没有明显的固体无机污染物,它们是无机发泡剂的残留物。 构成芳族聚酰亚胺泡沫的芳族聚酰亚胺的差示扫描量热法的玻璃化转变温度(Tg)为约235℃至约400℃。 并且通过热重分析(TGA)测定,在204℃下的热稳定性为0至约1%的重量损失。 芳族聚酰亚胺泡沫具有泡沫绝缘和结构泡沫的用途,例如用于航空航天和航海应用。
摘要:
A shaped article composed of an aromatic polyimide has a hollow, essentially spherical structure and a particle size of about 100 to about 1500 .mu.m, a density of about 1 to about 6 pounds/ft.sup.3 and a volume change of 1 to about 20% by a pressure treatment of 30 psi for 10 minutes at room temperature. A syntactic foam, made of a multiplicity of the shaped articles which are bonded together by a matrix resin to form an integral composite structure, has a density of about 3 to about 30 pounds/ft.sup.3 and a compression strength of about 100 to about 1400 pounds/in.sup.2.
摘要翻译:由芳族聚酰亚胺组成的成形制品具有中空的,基本上为球形的结构,并且具有约100至约1500μm的粒度,约1至约6磅/ ft 3的密度和1至约20%的体积变化,由 在室温下压力处理30psi 10分钟。 由多个成形制品制成的复合泡沫体,其通过基质树脂粘合在一起以形成整体复合结构,其密度为约3至约30磅/英3 3,压缩强度为约100至约1400磅 / in2。
摘要:
A shaped article composed of an aromatic polyimide has a hollow, essentially spherical structure and a particle size of about 100 to about 1500 &mgr;m, a density of about 1 to about 6 pounds/ft3 and a volume change of 1 to about 20% by a pressure treatment of 30 psi for 10 minutes at room temperature. A syntactic foam, made of a multiplicity of the shaped articles which are bonded together by a matrix resin to form an integral composite structure, has a density of about 3 to about 30 pounds/ft3 and a compression strength of about 100 to about 1400 pounds/in2.
摘要翻译:由芳族聚酰亚胺组成的成型制品具有中空的,基本上为球形的结构,并且具有约100至约1500μm的粒度,约1至约6磅/ ft 3的密度和1至约20%的体积变化, 在室温下压力处理30psi 10分钟。 由多个成形制品制成的复合泡沫体,其通过基质树脂粘合在一起以形成整体复合结构,其密度为约3至约30磅/英3 3,压缩强度为约100至约1400磅 / in2。
摘要:
High quality films, preimpregnated tape (prepegs) and composites have been fabricated from polyimide precursor “salt-like” solutions. These “salt-like” solutions have a low viscosity (5,000 to 10,000 cp) and a high solids content (50-65% by weight) and can be coated onto reinforcing fiber to produce prepegs with excellent tack and drape at 12-15% residual solvent (˜4-6% water from thermal imidization reaction). The processing of these types of prepegs significantly overcomes solvent removal problems and allows excellent fiber wet out. In addition, the physical characteristics of the polyimide precursor “salt-like” solutions permits processing into high-performance materials through the use of standard prepregging and composite fabrication equipment. The resultant composites are of high quality.
摘要:
A polyimide precursor solid residuum is an admixture of an aromatic dianhydride or derivative thereof and an aromatic diamine or dervative thereof plus a complexing agent, which is complexed with the admixture by hydrogen bonding. The polyimide precursor solid residuum is effectively employed in the preparation of polyimide foam and the fabrication of polyimide foam structures.
摘要:
Main chain thermotropic liquid crystal esters, ester-imides, and ester-amides were prepared from AA, BB, and AB type monomeric materials and were end-capped with phenylacetylene, phenylmaleimide, or nadimide reactive end-groups. The resulting reactive end-capped liquid crystal oligomers exhibit a variety of improved and preferred physical properties. The end-capped liquid crystal oligomers are thermotropic and have, preferably, molecular weights in the range of approximately 1000-15,000 grams per mole. The end-capped liquid crystal oligomers have broad liquid crystalline melting ranges and exhibit high melt stability and very low melt viscosities at accessible temperatures. The end-capped liquid crystal oligomers are stable for up to an hour in the melt phase. These properties make the end-capped liquid crystal oligomers highly processable by a variety of melt process shape forming and blending techniques including film extrusion, fiber spinning, reactive injection molding (RIM), resin transfer molding (RTM), resin film injection (RFI), powder molding, pultrusion, injection molding, blow molding, plasma spraying and thermo-forming. Once processed and shaped, the end-capped liquid crystal oligomers were heated to further polymerize and form liquid crystalline thermosets (LCT). The fully cured products are rubbers above their glass transition temperatures. The resulting thermosets display many properties that are superior to their non-end-capped high molecular weight analogs.
摘要:
A shaped article composed of an aromatic polyimide has a hollow, essentially spherical structure and a particle size of about 100 to about 1500 .mu.m, a density of about 1 to about 6 pounds/ft.sup.3 and a volume change of 1 to about 20% by a pressure treatment of 30 psi for 10 minutes at room temperature. A syntactic foam, made of a multiplicity of the shaped articles which are bounded together by a matrix resin to form an integral composite structure, has a density of about 3 to about 30 pounds/ft.sup.3 and a compression strength of about 100 to about 1400 pounds/in.sup.2.
摘要翻译:由芳族聚酰亚胺组成的成形制品具有中空的,基本上为球形的结构,并且具有约100至约1500μm的粒度,约1至约6磅/ ft 3的密度和1至约20%的体积变化,由 在室温下压力处理30psi 10分钟。 由多个成形制品制成的复合泡沫体,其通过基质树脂结合以形成整体复合结构,其密度为约3至约30磅/英3 3,压缩强度为约100至约1400磅 / in2。