Morphology and structure of poly(p-phenylene terephthalamide) crystallized from dilute organic solution

The high-temperature crystallization of poly(p-phenylene terephthalamide) (PPTA) from dilute organic solutions was achieved through the introduction of a non-solvent, or precipitating agent, at the desired crystallization temperature. The morphology and crystal structure were examined for crystals produced from PPTA polymer with two different molecular weights (M_w = 46000 and 3430 g mol⁻¹), using transmission electron microscopy. For the high-molecular-weight polymer, ribbon-like crystals were produced, while the low-molecular-weight polymer yielded small needles or platelets. In both cases, electron diffraction showed that the Northolt allomorph was obtained. For the high-molecular-weight polymer, the molecular axes were parallel to the ribbon axes in a chain-extended type structure. A hypothesis for the orientation of the low-molecular-weight PPTA in the small platelets, is also given.     

对苯二胺生产工艺条件的研究

对以铁 盐酸为还原体系 ,由对硝基苯胺制取对苯二胺的工艺条件进行了研究 ,研究了各种工艺条件如反应的配料、pH、温度、升华条件等对产率和产品质量的影响 ,获得了最佳的合成工艺。实验表明 :还原反应的反应温度在 95℃～ 10 5℃、pH为 3～ 4时 ,产率在 70 %以上 ;减压升华时油浴温度在 2 4 0℃ ,真空度为0 0 5MPa ,升华气相温度为 5 5℃～ 6 5℃时 ,产品的质量和白度达标     

Imide-aryl ether benzoxazole random copolymers

Novel imide-aryl ether benzoxazole copolymers were prepared and their morphology and mechanical properties investigated. A key feature of these copolymers is the incorporation of a benzoxazole moiety by the use of 2,2′-bis[4-(3-aminophenoxy)phenyl]-6,6′-bibenzoxazole or 2,2′-bis[4-(4-aminophenoxy)-phenyl]-6,6′-bibenzoxazole as co-diamines in polyimide syntheses. The preparation of these diamines involved the nucleophilic aromatic substitution of 2,2′-bis(4-fluorophenyl)-6,6′-bibenzoxazole with either 3- or 4-aminophenol in the presence of K₂CO₃. The diamines were co-reacted with various compositions of pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (ODA) to synthesize the desired poly(amic acids). Films were cast and cured (350°C) to effect the imide formation, affording films with elongations between 40 and 110% and moduli in the 2000–2750 MPa range. The copolymers exhibited good dimensional (T_g in excess of 300°C) and thermal stability. Wide-angle X-ray diffraction measurements on the copolymers showed that the ordered morphology characteristic of PMDA/ODA polyimide was retained. Improvements in the auto-adhesion were observed, particularly in those copolymers which displayed a T_g.     

二氧化碳法制备六亚甲基二异氰酸酯的研究

研究了二氧化碳与己二胺甲氧羰基化反应合成六亚甲基二异氰酸酯，考察了有机碱用量、反应温度、反应时间和压力等操作条件对反应的影响。结果表明最佳工艺条件：n（三乙胺）：n（己二胺）=3：1，反应温度-5℃、反应时间60min、压力为0．55MPa。并用红外谱图和折光率对合成产物进行表征。     

水体中苯胺类化合物测定方法的改进

本文分别利用活性炭吸附、三氯甲烷萃取和前两种方法联用对显色剂 N-(1 -萘基 )乙二胺进行了提纯 ,从而使水体中苯胺类化合物测定方法的显色时间由 1 2 0 min(未提纯法 )缩短至 90 min(经三种方法提纯 ) ,显色剂溶液的稳定性有了明显的提高 ,测定方法的精密度得到了显著的改善 ,同时检出限也由 0 .3 0 mg/L (未提纯法 )分别降至 0 .0 48mg/L (活性炭吸附提纯法 )、0 .0 59mg/L(三氯甲烷萃取提纯法 )和 0 .0 3 1 mg/L(两种方法联用提纯法 ) ,用经三种方法提纯后的显色剂溶液测定水样中的苯胺 ,测定结果均令人满意     

一类含查尔酮结构的光敏性二胺的合成研究

以醛、酮为原料经羟醛缩合反应合成了具有一类含查尔酮结构的光敏性二胺:1-(3-氨基苯基)-3-(4-氨基苯基)-2-丙烯-1-酮与对-二(间氨基肉桂酰)苯.通过优化实验得到最佳的合成工艺为:醛、酮在温度为0℃下,以乙醇为溶剂,氢氧化钠为催化剂,进行羟醛缩合反应3h.收率可达到86%,经液相色谱分析其纯度分别为99.92%,99.91%,紫外可见最大吸收波长分别为349nm、361nm.所得方法操作简便,收率较高,原料易得.并用元素分析、核磁共振、红外光谱等手段对产物的结构进行了表征.     

PPTA／尼龙1010分子复合材料流变行为的研究

本文采用共沉淀法制备了聚对苯二甲酰对苯二胺(PPTA)/尼龙1010分子复合材料。测定了PPTA/尼龙1010分子复合材料的流变行为,发现PPTA使尼龙1010的表观熔体粘度变大,且PPTA/尼龙1010分子复合材料的表观熔体粘度对温度的敏感性不象尼龙1010那样突出。     

Magnetic Behavior of Trinuclear Vanadium(II)–Diamine Complexes. Part 2. Large Intramolecular Antiferromagnetic Exchange Interactions in a Triangular Unit

This study reports the magnetic structures of newly reported trinuclear vanadium(II)–diamine complexes. Using the isotropic Heisenberg exchange Hamiltonian, it is suggested that there are strong intramolecular antiferromagnetic interactions among the vanadium(II) ions. It is also suggested that these complexes are good candidates to the geometrically frustrated systems. For part 1 see A. Bayri, J. Inorg. Organomet. Polym. Mater., (in press) An erratum to this article can be found at     

二苯并（2，3，2＇，3＇，bg）－1H，6H，1，4，6，9－四氮－5－钛螺环［4，4］－5，5－二氯化物

ｏ－苯二胺与四氯化钛反应合成聚合物的模型化合物钛杂咪唑啉。该化合物经元素分析、红外光谱、质谱测试。     

原位缩聚合成含聚芳酰胺／酯的微相复合物 Ⅲ．全芳聚酰胺与聚酯-聚醚体系的研究

对于聚对苯二甲酰对苯二胺(PPTA)和PBT-PTMG体系,比较了溶剂配比(CH2Cl2／NMP)、聚合物浓度、强极性溶剂的用量和加料方式对缩聚反应的影响。发现溶剂配比、基体聚合物PBT-PTMG影响PPTA的转化率和PPTA的分子质量。通过FTIR研究发现PPTA中的酰胺键-NH-和PBT-PTMG的醚键特征吸收均向低渡数位移;通过用PBT-PTMG 的良溶剂二氯甲烷对复合物进行产抽提,结果发现,刚性链PPTA与PBT-PTMG分子链有较强的氢键相互作用,从而改进了分子间的相容性,获得了PPTA／PBT-PTMG的微相复合物。PPTA／PBT-PTMG的微相复合物有较好的力学性能。