Crystallography and Structure–Property Relationships in 2,2′,2″,2′′′,4,4′,4″,4′′′,6,6′,6″,6′′′‐Dodecanitro‐1,1′ : 3′1″ : 3″,1′′′‐ Quaterphenyl (DODECA)

X‐ray crystallographic study of 2,2′,2″,2′′′,4,4′,4″,4′′′,6,6′,6″,6′′′‐dodecanitro‐1,1′ : 3′1″ : 3″,1′′′‐quaterphenyl (DODECA) has been carried out. Nonbonding interatomic distances of oxygen atoms inside of all the nitro groups are shorter than those corresponding to the intermolecular contact radii for oxygen. By means of the DFT B3LYP/6‐31(d, p) method a difference of 136 kJ mol⁻¹ between the X‐ray and DFT structures of DODECA was found. The bearer of the highest initiation reactivity in its molecule in solid phase should be the nitro group at 4′′′‐position, in contrast to those at 2′‐ or 2″‐positions in its isolated molecule. The most reactive nitro group in the DODECA molecule can be well specified by the relationship between net charges on nitro groups and charges on their nitrogen atoms, both of them for the X‐ray structure. The ¹⁵N chemical shift, corresponding to this nitro group for the initiation by impact and shock, correlates very well with these shifts of the reaction centers of the other six “genuine” polynitro arenes.     

Syntheses and Biological Activities of Polymers Containing 3′-Azido-3′-deoxythymidine

The new monomer, 5′-O-methacryloyl-3′-azido-3′-deoxythymidine (MAZT), was synthesized by the reaction of methacryloyl chloride and 3′-azido-3′-deoxythymidine (AZT). Poly(MAZT) and copolymers of MAZT with vinyl acetate (VAc) and maleic anhydride (MAH) were synthesized by radical polymerizations. The synthesized MAZT and polymers were identified by ¹H nuclear magnetic resonance (NMR), ¹³C NMR, elemental analysis and gel permeation chromatography. The quantities of MAZT units in poly(MAZT-co-VAc) and poly(MAZT-co-MAH) were 45 and 27 mol%, respectively. The weight average molecular weights of the polymers synthesized were in the range from 8800 to 17600. The in vitro cytotoxicities of samples against K562 human leukaemia cell line at 100 μg ml^-1 decreased in the following order: poly(MAZT-co-MAH) > poly(MAZT-co-VAc) > poly(MAZT) > MAZT > AZT. The in vivo anti-tumour activities of the polymers synthesized against Balb/C mice bearing sarcoma 180 tumour cells were greater than those of 5-fluorouracil at all concentrations.     

Crystallography and Structure–Property Relationships of 2,2″,4,4′,4″,6,6′,6″‐Octanitro‐1,1′ : 3′,1″‐Terphenyl (ONT)

An X‐ray crystallographic study of 2,2″,4,4′,4″,6,6′,6″‐octanitro‐1,1′ : 3′,1″‐terphenyl (ONT) has been carried out. The dihedral angles between benzene rings vary from 84.9° to 89.4°. Nonbinding interatomic distances of oxygen atoms inside all the nitro groups are shorter than the intermolecular contact radii for oxygen. On the basis of the DFT B3LYP/6‐31(d, p) method it was found that the difference between the X‐ray structure in the solid phase and DFT result for the gas phase is 98 kJ mol⁻¹, and the bearer of the highest initiation reactivity of the ONT molecule in the solid phase should be the nitro group at 4″‐position, in contrast to those at 4′‐ or 6′‐position that play this role in the isolated molecule. It has been stated that the nitro groups at the reaction centers of the ONT molecule are relatively well specified by their ¹⁵N NMR chemical shifts.     

Investigation of the Solubility of 3,4‐Diaminofurazan (DAF) and 3,3′‐Diamino‐4,4′‐azoxyfurazan (DAAF) at Temperatures Between 293.15 K and 313.15 K

The solubilities of 3,4‐diaminofurazan (DAF) and 3,3′‐diamino‐4,4′‐azoxyfurazan (DAAF) were investigated in water, dichloromethane, acetonitrile, ethyl acetate, methanol, and acetone between 293.15 K and 313.15 K. The solubility was determined by high‐pressure liquid chromatography with ultraviolet detection. The solubilities of DAF and DAAF are increased with the increasing of temperature in all solvents studied. The enthalpy of solution in each solvent was calculated according to van't Hoff Equation.     

Synthesis and properties of poly(amide–imide)s based on N,N′‐bis(4‐carboxyphenyl)‐4,4′‐oxydiphthalimide,p‐aminobenzoic acid and various aromatic diamines

A new diimide–diacid monomer, N,N′‐bis(4‐carboxyphenyl)‐4,4′‐oxydiphthalimide (I), was prepared by azeotropic condensation of 4,4′‐oxydiphthalic anhydride (ODPA) and p‐aminobenzoic acid (p‐ABA) at a 1:2 molar ratio in a polar solvent mixed with toluene. A series of poly(amide–imide)s (PAI, III_a–m) was synthesized from the diimide–diacid I (or I′, diacid chloride of I) and various aromatic diamines by direct polycondensation (or low temperature polycondensation) using triphenyl phosphite and pyridine as condensing agents. It was found that only III_k–m having a meta‐structure at two terminals of the diamine could afford good quality, creasable films by solution‐casting; other PAIs III using diamine with para‐linkage at terminals were insoluble and crystalline; though III_g–i contained the soluble group of the diamine moieties, their solvent‐cast films were brittle. In order to improve their to solubility and film quality, copoly(amide–imide)s (Co‐PAIs) based on I and mixtures of p‐ABA and aromatic diamines were synthesized. When on equimolar of p‐ABA (m = 1) was mixed, most of Co‐PAIs IV had improved solubility and high inherent viscosities in the range 0.9–1.5 dl g^?1; however, their films were still brittle. With m = 3, series V was obtained, and all members exhibited high toughness. The solubility, film‐forming ability, crystallinity, and thermal properties of the resultant poly(amide–imide)s were investigated. © 2002 Society of Chemical Industry     

Bis(4′-phenyl-2,2′:6′,2″-terpyridine)ruthenium(II): Holding the {Ru(tpy)2} embraces at bay

The solid state structure of [Ru(Phtpy)₂][PF₆]₂ · 4MeCN has been determined (Phtpy = 4′-phenyl-2,2′:6′,2″-terpyridine); [Ru(Phtpy)₂]²⁺ cations pack into sheets by virtue of {M(tpy)₂}₂ embraces, and the MeCN solvent molecules are involved in NH–C interactions which prevent the efficient packing of adjacent sheets. Comparisons with related structures lead to some generalizations about packing motifs in salts containing [M(Phtpy)₂]²⁺ or [M(pytpy)₂]²⁺ cations (pytpy = 4′-pyridyl-2,2′:6′,2″-terpyridine).     

Two novel Zn(II) coordination polymers based on trigonal ligand: 4′-(4-pyridyl)-3,2′:6′,3″-terpyridine

Two novel Zn(II) coordination polymers, [Zn₅(pytpy)₈(fum)₄(H₂O)₄(OH)₂]_n · n(CH₃OH) · 2n(H₂O) (1) and [Zn₃(pytpy)₄ (btc)₂]_n · 2n(H₂O) (2) (pytpy = 4′-(4-pyridyl)-3,2′:6′,3″-terpyridine, H₂fum = fumaric acid, H₃btc = 1,3,5-benzenetricarboxylic acid) have been hydrothermally synthesized and structurally characterized. Complex 1 is a 2D layer structure, which is constructed from linear pentanuclear Zn(II) subunits interconnected via bidentate-bridging pytpy ligands and tridentate-bridging fum²⁻ anions. Complex 2 is a 3D network structure, μ₂-pytpy ligands link the layers based on the heart-like hexanuclear subunits to form the 3D network. Both complexes show strong fluorescence emission upon excitation at 310 nm in solid state. Additionally, these two complexes possess great thermal stabilities, especially for 2, the framework is stable up to 350 °C.     

聚氯乙烯/埃洛石纳米管复合材料的制备与性能研究

通过熔融混炼法制备了聚氯乙烯（PVC）/埃洛石纳米管（HNTs）复合材料,通过力学性能测试和扫描电子显微镜、透射电子显微镜等方法研究了HNTs含量对复合材料形貌与性能的影响,并分析了HNTs的作用机理。结果表明,HNTs可以对PVC产生增强增韧的作用;PVC/HNTs复合材料的储能模量和玻璃化转变温度相对纯PVC均有所增加;不同含量的HNTs在PVC基体中的分散性均较好且无大面积团聚的现象;HNTs与PVC间具有较强的界面作用力,其界面作用半经验参数（B）值为4.35。     

An investigation of cure and thermal stability of poly(amide‐amidic acid) modified tetraglycidyl 4,4′‐diaminodiphenylmethane/4,4′‐diaminodiphenylsulfone

In this work, poly(amide‐amidic acid) (PAA) was used to modify tetraglycidyl 4,4′‐diaminodiphenylmethane (TGDDM)/4,4′‐diaminodiphenylsulfone (DDS) system. Results of non‐isothermal differential scanning calorimetry analysis indicated that PAA played a role of catalyst during the process of the curing reaction. The curing mechanism was studied by Fourier transform infrared spectroscopy, showing that the PAA acted as a co‐curing agent in the system. The glass transition temperature decreased firstly and then increased with the increase of the PAA content. PAA equally rendered TGDDM more fire resistant with higher char yield. On examining the fracture surface morphology using scanning electron microscopy, it was observed that there was no obvious phase separation when the content of PAA was less than 20 phr (per hundred weight of TGDDM/DDS resin), however, phase separation was observed when the content of PAA was 25 and 30 phr. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and properties of TLCPs with 2,6‐naphthalene‐based mesogen,polymethylene spacer,and nonlinear 4,4′‐thiodiphenyl links

A series of new thermotropic main‐chain liquid crystalline copolyesters were prepared by polycondensation of 2,6‐naphthalenedicarbonyl chloride, 4,4′‐thiodiphenol, and α,ω‐alkanediols (n = 4–10) in diphenyl ether at 200°C. Thermal transition behaviors of these copolyesters were investigated by differential scanning calorimetry. Moreover, their thermal stabilities and mesomorphic textures were studied by thermogravimetric analysis and polarizing optical microscopy, respectively. Corresponding model compounds with terminal mesogenic units and central polymethylene spacers were also synthesized for comparison. Both copolymers and model compounds exhibit odd–even dependency of melting temperatures, transition enthalpy (ΔH_m), and entropy (ΔS_m) on the number of methylene units in the spacer. However, the odd–even effects in model compounds are much more distinctive. Nematic mesophases are the only texture observed in melts, except the model compounds with longer methylene units (n = 8, 10), in which smectic mesophases can be observed. The T_m values of the copolyesters (TDP/HD = 1/1) are between 233 and 259°C, depending on spacer length. The initial decomposition temperatures of the copolyesters are above 419°C under N₂ atmosphere. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1536–1546, 2002     

改性聚天冬氨酸/聚丙烯酸复合吸水性树脂的制备与敏感性研究

以丙烯酸(AA)为单体,过硫酸钾(KPS)为引发剂,改性聚天冬氨酸(MKPAsp)作为交联剂,通过水溶液聚合法制得新型改性聚天冬氨酸/聚丙烯酸(MKPAsp/PAA)复合吸水性树脂。通过红外光谱、热失重分析(TGA)和扫描电镜(SEM)对复合吸水性树脂进行了表征。SEM表明AA的加入,改善了孔道结构,使孔密度增加,孔径更加均匀规则。研究了具有不同组成复合吸水性树脂在不同温度、pH和盐溶液中的溶胀性能,结果表明MKPAsp/PAA复合吸水性树脂低临界溶解温度(LCST)比聚天冬氨酸(KPAsp)提高了10℃,表现出良好的温度敏感性;在pH为6和10的溶液中出现2个吸液峰值;复合吸水性树脂的耐盐性较KPAsp得到了提高,且在不同价态的氯盐中吸液倍率顺序为Na~+Fe~(3+)Ca~(2+)。制得的MKPAsp/PAA复合吸水性树脂在去离子水和90mmol/L的Na Cl溶液中的最佳吸液倍率达到886.7和165.1 g/g,分别比KPAsp树脂提高了3.8倍和2.3倍。     

聚氯乙烯／十二烷基硫酸根柱撑水滑石复合材料的结构与性能

通过离子交换反应制备了十二烷基硫酸根柱撑水滑石(HT-SDS)，进而利用聚氯乙烯(PVC)与HT-SDS熔融共混加工和HT-SDS存在条件下的氯乙烯原位悬浮聚合两种方法制备了PVC／水滑石(PVC／HT)复合材料，并对复合材料的结构和性能进行了研究。发现采用前一种方法得到的复合材料中水滑石分散尺寸大多在100nm以上，而采用后一种方法得到的复合材料中水滑石均匀、取向分散在PVC基体中，至少有一维尺寸小于100nm。随着水滑石含量增加，PVC的热稳定性提高，而玻璃化温度变化不大。采用后一种方法得到的复合材料的拉伸性能和冲击性能明显优于采用前一种方法得到的复合材料。     

Miscibility and crystallization behavior of the solution‐blended sulfonated poly(phenylene oxide)/ poly(styrene‐co‐4‐vinyl pyridine) blend

The miscibility and crystallization behavior of the solution‐blended lightly sulfonated poly(phenylene oxide) (SPPO)/poly(styrene‐co‐4‐vinylpyridine) (PSVP) blend were investigated by conventional and modulated differential scanning calorimetry (MDSC). It was found that the original blend film is actually composed of a crystalline SPPO phase and a noncrystalline compatible SPPO–PSVP phase. The original phase‐segregated structure will evolve to a noncrystalline homogenous structure by subsequent high temperature annealing. The resulting good miscibility was attributed to two aspects: one is that the SPPO crystalline structure could be destroyed as annealing temperature is high enough; the other is that the acid–base interaction between the sulfonic group of SPPO and the pyridine ring of PSVP could promote mixing of different components effectively. And such acid–base interaction was demonstrated by ¹C NMR spectra. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2843–2848, 2001     

Modification of bismaleimide resin by poly(ethylene phthalate‐co‐ethylene terephthalate), poly(ethylene phthalate‐co‐ethylene 4,4′‐biphenyl dicarboxylate), and poly(ethylene phthalate‐co‐ethylene 2,6‐naphthalene dicarboxylate)

Aromatic polyesters were prepared and used to improve the brittleness of bismaleimide resin, composed of 4,4′‐bismaleimidodiphenyl methane and o,o′‐diallyl bisphenol A (Matrimid 5292 A/B resin). The aromatic polyesters included PEPT [poly(ethylene phthalate‐co‐ethylene terephthalate)], with 50 mol % of terephthalate, PEPB [poly(ethylene phthalate‐co‐ethylene 4,4′‐biphenyl dicarboxylate)], with 50 mol % of 4,4′‐biphenyl dicarboxylate, and PEPN [poly(ethylene phthalate‐co‐ethylene 2,6‐naphthalene dicarboxylate)], with 50 mol % 2,6‐naphthalene dicarboxylate unit. The polyesters were effective modifiers for improving the brittleness of the bismaleimide resin. For example, inclusion of 15 wt % PEPT (MW = 9300) led to a 75% increase in fracture toughness, with retention in flexural properties and a slight loss of the glass‐transition temperature, compared with the mechanical and thermal properties of the unmodified cured bismaleimide resin. Microstructures of the modified resins were examined by scanning electron microscopy and dynamic viscoelastic analysis. The toughening mechanism was assessed as it related to the morphological and dynamic viscoelastic behaviors of the modified bismaleimide resin system. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2352–2367, 2001     

Fabrication and Physical Properties of Poly(ε‐Caprolactone)/Modified Graphene Nanocomposite

A chemical strategy is attempted to modify graphene for its facilitated dispersion in poly(ε‐caprolactone) (PCL) matrix. Herein, graphite oxide is subjected to sequential treatment with phenyl isocyanate and vitamin C (VC) to yield graphene nanosheets (iG‐VC). It is noteworthy that following the reduction treatment, iG‐VC graphene sheets exfoliate within the PCL matrix and show appreciable interfacial compatibility with PCL matrix in organic solvent by virtue of improved polarity from isocyanate treatment. The tensile yield strength and Young's modulus of the PCL/iG‐VC composite exhibit pronounced enhancement as compared to neat PCL, despite of mere composition of graphene sheets. The tensile yield stress of composite is increased notably to reach 18.6 MPa at 3 wt% graphene sheets as compared to neat PCL. Likewise, Young's modulus of composite is observed to increase from 370 to 470 MPa at 5 wt% graphene sheets. Moreover, the crystallization temperature (T _c) and crystallinity of PCL increase significantly upon incorporation of small amount of iG‐VC. Ultimately, functional role of iG‐VC graphene sheets is demonstrated in enhancing electrical conductivity of PCL‐based nanocomposites. The plausible mechanisms are also proposed to explain the increased T _c, improved mechanical property, and improved electrical conductivity of PCL/iG‐VC composite.

     

聚氯乙烯/纳米氧化铝复合材料的制备与性能

利用硅烷偶联剂（KH 550）对纳米氧化铝进行有机化处理,并通过熔融共混制备了聚氯乙烯/纳米氧化铝复合材料。通过红外分析对纳米氧化铝进行了表征,采用扫描电子显微镜观察了纳米氧化铝在聚氯乙烯树脂中的分散状况,并对复合材料的热性能和力学性能进行了研究。结果表明,经过表面改性的纳米氧化铝粒子在PVC基体中分布均匀;加入纳米氧化铝改善了复合材料的热性能和力学性能;当纳米氧化铝含量为3.0 %（质量分数,下同）时,复合材料的拉伸强度和冲击强度相对于纯聚氯乙烯材料分别提高了16.25 %和20.27 %。     

Synthesis and characterization of novel polyaspartimides derived from 2,2′‐dimethyl‐4,4′‐bis(4‐maleimidophenoxy)biphenyl and various diamines

A novel bismaleimide, 2,2′‐dimethyl‐4,4′‐bis(4‐maleimidophenoxy)biphenyl, containing noncoplanar 2,2′‐dimethylbiphenylene and flexible ether units in the polymer backbone was synthesized from 2,2′‐dimethyl‐4,4′‐bis(4‐aminophenoxy)biphenyl with maleic anhydride. The bismaleimide was reacted with 11 diamines using m‐cresol as a solvent and glacial acetic acid as a catalyst to produce novel polyaspartimides. Polymers were identified by elemental analysis and infrared spectroscopy, and characterized by solubility test, X‐ray diffraction, and thermal analysis (differential scanning calorimetry and thermogravimetric analysis). The inherent viscosities of the polymers varied from 0.22 to 0.48 dL g⁻¹ in concentration of 1.0 g dL⁻¹ of N,N‐dimethylformamide. All polymers are soluble in N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, N,N‐dimethylformamide, dimethylsulfoxide, pyridine, m‐cresol, and tetrahydrofuran. The polymers, except PASI‐4, had moderate glass transition temperature in the range of 188°–226°C and good thermo‐oxidative stability, losing 10% mass in the range of 375°–426°C in air and 357°–415°C in nitrogen. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 279–286, 1999     

Copolycondensation of IPA/TPA,BPA, and 4,4′‐dihydroxydipehnylsulfone and 4,4′‐dicarboxydiphenylsulfone

Copolycondensations of IPA, TPA, bisphenol A (BPA), and several cimonomers were carried out to improve thermal properties, such as, the glass transition temperature (T_g) of the IPA/TPA (50/50)–BPA polyester. Among the comonomers examined, 4,4′‐Dihydroxydiphenylsulfone (BPS) and 4,4′‐Dicarboxydiphenylsulfone (DCDPS) having a strongly dipolar sulfonyl group in the chain were significantly effective. The favorable effect upon the T_gs was studied by varying the amounts of BPS and DCDPS incorporated into the copolymers. In the copolycondensation with BPS, two‐stage copolycondensation of BPA first and then BPS, the reverse order of reaction, and their spontaneous addition were examined to investigate the effect of distribution of the BPS unit segments in the copolymer upon the T_gs of the resulted copolymers. The distribution was briefly studied from distribution of the IPA/TPA‐BPA oligomers in the initial reaction using GPC. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 875–879, 2000     

聚乳酸/植物纤维全生物降解复合材料的研究进展

综述了聚乳酸(PLA)/植物纤维复合材料的研究现状,分别从植物纤维的来源及类型、纤维和PLA基体的界面改性、复合材料的制备方法等方面介绍了复合材料的研究进展。最后,展望了PLA/植物纤维全生物降解复合材料的发展趋势。