Different crystallinity of poly(d,l-lactide-co-p-dioxanone) copolymers acquired by control of chain microstructure

Poly（d,l-lactide-co-p-dioxanone） （P（LA-co-PDO）） copolymers with different chain microstructures were synthesized by onestep or two-step bulk ring-opening polymerizations of d,l-lactide （LA） and p-dioxanone （PDO） monomers using stannous octoate [Sn（Oct）2]/n-dodecanol as the initiating system. The average sequence lengths of the lactidyl （LLA） and dioxanyl （LpDo） units were calculated from the ^1H NMR spectra. It was found that both LLA and Lpoo values from the two-step syntheses were significantly longer than those from the corresponding one-step syntheses, indicating more blocky structure achieved for the twostep copolymers. Corresponding to this difference in microstructure, the two-step copolymers were semi-crystalline, while the one-step copolymers were completely amorphous. In conclusion, the crystallinity of P（LA-co-PDO） copolymers could be adjusted conveniently to meet specific applications by changing the microstructure of the copolymers via different polymerization routes.

Design,synthesis and characterization of novel biodegradable macrodiols based on poly(DL-lactic acid) and poly(p-dioxanone)

Integrating poly（lactic acid） （PLA）, glycolic acid （GA） and ethylene glycol （EG） will hopefully result in a novel copolymer that combines such advantages as fastened and controllable release rate and improved flexibility together with good biocompatibility. In this study, p-dioxanone （PDO） was employed to copolymerize with DL-lactide （LA） via ring-opening melt polymerization using Sn（Oct）2 as an initiator and ethylene glycol as a co-initiator. The obtained degradable macrodiols （HO-P（LA-co-PDO）-OH） were just such a copolymer consisting of PLA, GA and EG. 1HNMR was employed to characterize the copolymers, and the effect of PDO/LA molar ratios in the feedstock on the molecular weights of HO-P（LA-co-PDO）-OH was investigated by means of endhydroxyl analysis, 1H NMR or GPC-MALLs. The results confirmed the successful synthesis of HO-P（LA-co-PDO）-OH and revealed that one end-hydroxyl of the micarodiols was donated by LA or PDO and the other one by the co-initiator EG. In addition, the molecular weights of HO-P（LA-co-PDO）-OH increased with decreasing PDO/LA ratios.

Enzymatic Synthesis and Characterization of Novel Amphiphilic Triblock Copolymer Poly(p-dioxanone-co-5-benzyloxytrimethylene carbonate)-block-poly(ethylene glycol)

Novel amphiphilic triblock copolymer poly（p-dioxanone-co-5-benzyloxytrimethylene carbonate）-block-poly（ethylene glycol）-block-poly（p-dioxanone-co-5-benzyloxytrimethylene carbonate） （p（PDO-co-BTMC）-b-PEG-b-p（PDO-co-BTMC）） was successfully synthesized using immobilized porcine pancreas lipase on porous silica particles （IPPL） as the catalyst for the fLrSt time. 1H NMR, 13C NMR and GPC analysis were used to confirm the structures of resulting copolymers. The molecular weight （Mn） of the copolymer with feed ratio of 69：20：11 （BTMC： PDO： PEG ） was 31300 g/mol and the polydispersity was 1.85, while the Mn decreased to 25000 g/mol and polydispersity of 1.93 with the feed ratio of 50：40：10.

Biodegradable Radiopaque Composite Filaments Based on Poly(p-dioxanone)and 2,3,5-triiodobenzoic Acid

To determine the possibility of blending 2, 3, 5-triiodobenzoic acid( TIBA) and poly( p-dioxanone)( PPDO) to produce X-ray visible PPDO filaments,melt-blended PPDO with different concentrations of TIBA was obtained. Several radiopaque filaments of PPDO polymer filled with radiopaque TIBA particles were prepared via melt-blending. Material properties of the composite filaments were investigated using various material characterization techniques,including scanning electron microscope( SEM),thermogravimetric analysis( TGA),X-ray Diffraction( XRD),dynamic rheometry and micro-CT scan. In this article,the dispersion of TIBA in PPDO,the properties of the filament,and the ratio of PPDO and TIBA and the corresponding X-ray visibility in vivo were studied. SEM results showed the dispersion of the contrast imaging agent TIBA was relatively even in the PPDO polymer. Xray analysis in vitro confirmed the enhanced radiopacity of the filaments with respect to the pure PPDO filament. The presence of iodine element in the composite filament could allow the bioabsorbable material to be monitored in vivo, and made it potential to be used in biomedical applications.

PBO纤维表面改性处理的研究进展

聚对苯撑苯并二噁唑(PBO)纤维因其比强度高、比模量高、耐热性好、阻燃性好以及优异的介电性能,现已在安全防护、建筑汽车等领域得到广泛应用。由于PBO纤维表面光滑、化学惰性,导致其与基体树脂界面结合差,进一步影响复合材料的整体性能,这大大限制了PBO纤维优异综合性能的发挥,所以对PBO纤维表面进行改性处理显得尤为重要。介绍了近年来国内外针对PBO纤维不同表面改性方法及对应复合材料性能改善程度的研究进展,从PBO纤维改性方法的分类入手,阐述了各种方法的基本原理。通过对这些处理方法的比较,阐述了国内PBO纤维表面改性的研究进展,指出了国内外在PBO纤维表面改性处理上的差距,为未来的发展方向提供了参考。PBO纤维表面改性方法包括化学刻蚀法、等离子体处理、表面涂层法、化学接枝法、紫外刻蚀法、上浆剂处理等。各种改性技术各有利弊,在选择改性方法时,理应考虑达到工艺快捷有效、经济环保和无损纤维性能等指标。未来,在PBO纤维表面改性的处理方法领域,将逐步向绿色环保的上浆剂处理方向发展。

具有多晶阻挡层的浮空P区IGBT开关特性研究

为了减少浮空P区IGBT结构的栅极空穴积累,改善结构的电磁干扰(EMI)噪声问题,从而提高结构电磁干扰噪声与开启损耗(Eon)之间的折中关系,研究提出了一种具有多晶硅阻挡层的FD-IGBT结构。新结构在传统结构的浮空P区上方引入一块多晶硅阻挡层,阻挡层接栅极,形成与N型漂移区的电势差。新结构在器件开启过程中,多晶硅阻挡层下方会积累空穴,导致栅极附近积累的空穴数量减少,从而降低浮空P区对栅极的反向充电电流。通过TCAD软件仿真结果表明,相比于传统FD-IGBT,新结构开启瞬态的过冲电流(I_(CE))和过冲电压(V_(GE))的峰值分别下降26.5%和8.6%,且在栅极电阻(R_(g))增加时有更好的电流电压可控性;相同开启损耗下,新结构的dI_(CE)/dt、dV_(CE)/dt和dV_(KA)/dt最大值分别降低26.5%,15.1%和26.1%。

PDO机织气管支架在体外有菌环境下的降解性能

人体气道环境是一个有菌的动态环境,植入气管中的聚二恶烷酮(PDO)支架在降解过程中易受细菌环境的干扰。探讨了体外有菌环境下PDO机织气管支架的降解性能,分析了细菌对PDO机织气管支架降解行为的影响。试验结果显示,细菌的存在对气管支架的降解有积极作用,它在降解前期能够缓冲溶液pH值的变化,减小支架的降解速率,使支架保持足够的径向支撑力,在降解后期能够加速支架的降解,使支架尽快被吸收;不同菌株对支架的侵蚀程度存在差异;机织结构的交织点会导致成品支架的降解形态呈现出不均匀性。研究可为PDO机织气管支架的进一步开发应用提供参考。

耐高温尼龙PA6T-66的阻燃改性研究

探究了二乙基次磷酸铝(OP1230)和二氧化硅(SiO2)复配使用对聚对苯二甲酰己二胺/己二酰己二胺(PA6T-66)树脂的阻燃协效作用。结果表明:OP1230的加入可显著提高材料的极限氧指数(LOI),当OP1230质量分数为6.0%时,材料的LOI从21.8%(未添加OP1230)提高至28.7%,且UL-94阻燃测试达到了V-2级。在此基础上,通过复配SiO2进一步提高材料阻燃性能。当SiO2质量分数为3.0%时,材料的LOI提高至29.4%,UL-94阻燃测试达到了V-0级。热氧降解和锥形量热数据也进一步证明OP1230和SiO2在PA6T-66阻燃体系中存在协效作用。

PBO纤维/间位芳纶混纺水刺非织造布的热防护性能

设计制备了3组不同混纺比的聚对苯撑苯并二噁唑(PBO)纤维/间位芳纶混纺水刺非织造布隔热层面料,PBO纤维与间位芳纶的质量比分别为10/90、20/80和30/70。将制备的PBO纤维/间位芳纶混纺水刺非织造布与市售常规芳纶隔热水刺非织造布(对位芳纶与间位芳纶质量比为20/80)进行性能测试对比,探究不同混纺比PBO纤维/间位芳纶混纺水刺非织造布的热防护性能和应用潜力。研究结果表明:3组PBO纤维/间位芳纶混纺水刺非织造布均表现出优异的热防护效果,没有因PBO纤维的高导热率而降低灭火服组合的热防护性能,其中,PBO纤维与间位芳纶混纺比为20/80时,混纺水刺非织造布的热防护性能最佳。

p型TOPCon技术及其在高效晶体硅太阳电池应用的研究进展

隧穿氧化硅钝化接触(TOPCon)晶体硅太阳电池被广泛认可为下一代高效太阳电池技术,n型TOPCon技术已成为当前新上生产线的主流方案。p型TOPCon技术虽然更加适合p型晶体硅太阳电池产业生态,却因其关键钝化接触性能提升困难、已有技术方案不适合量产等因素而发展缓慢。基于p型TOPCon技术的重要性,详细介绍了p型TOPCon技术的研究进展,并探讨了制约该技术钝化性能提升的关键科学问题。从国内外的研究结果来看,分别基于LPCVD技术及PECVD技术的p型TOPCon技术在钝化性能上均取得了进步,获得最高隐含开路电压(对应的最低单面饱和电流密度)分别达到737 mV(2 fA/cm^(2))和732 mV(约5 fA/cm^(2))的p型TOPCon结构,已初步显示出产业应用潜力。开发具有产业应用价值的p型TOPCon技术对晶体硅太阳电池产业的发展具有重要意义,值得全行业进一步深入研究。

Poly (Acrylamide-co-Acrylic Acid) Hydrogel Induced by Glow-Discharge Electrolysis Plasma and Its Adsorption Properties for Cationic Dyes

In this paper, poly （acrylamide-co-acrylic acid） （P（AM-co-AA）） hydrogel was pre- pared in an aqueous solution by using glow-discharge electrolysis plasma （GDEP） induced copoly- merization of acrylamide （AM） and acrylic acid （AA）, in which N,N＇-methylenebisacrylamide （MBA） was used as a crosslinker. A mechanism for the synthesis of P（AM-co-AA） hydrogel was proposed. To optimize the synthesis condition, the following parameters were examined in detail： the discharge voltage, discharge time, the content of the crosslinker, and the mass ratio of AM to AA. The results showed that the optimum pH range for cationic dyes removal was found to be 5.0-10.0. The P（AM-co-AA） hydrogel exhibits a very high adsorption potential and the ex- perimental adsorption capacities for Crystal violet （CV） and Methylene blue （MB） were 2974.3 mg/g and 2303.6 mg/g, respectively. The adsorption process follows a pseudo-second-order kinetic model. In addition, the adsorption mechanism of P（AM-co-AA） hydrogel for cationic dyes was also discussed.

医用PPDO倒刺缝合线的体外降解性能

可降解倒刺缝合线的降解过程需要与伤口愈合时间相适应,为了深入研究聚对二氧环己酮(poly(p-dioxanone),PPDO)倒刺缝合线的倒刺结构及缝合线规格对其降解情况的影响,采用多种规格的PPDO倒刺缝合线和PPDO光滑缝合线进行体外实时降解试验对比。结合不同降解时间点,对缝合线的形貌、直径、质量、热力学性能、红外光谱及力学性能的变化情况进行分析。研究结果表明:倒刺缝合线在降解8星期(56d)内的各项性能较稳定,可在伤口愈合过程中为软组织提供一定的力学支持,但8星期后缝合线发生碎裂且降解过程加快,倒刺结构和缝合线规格对PPDO缝合线的降解无明显影响。研究为后续PPDO倒刺缝合线体内降解试验和临床应用提供了依据。

Synthesis and Adsorption Property of Two Polymeric Adsorbents with Pendent Ether Bonds

Two polymeric adsorbents, poly(methyl p-vinylbenzyl ether) and poly(phenyl p-vinylbenzyl ether), were synthesized from chloromethylated polystyrene. Their adsorption property for phenol in hexane solution was investigated. The results showed that the two adsorbents adsorb phenol from hexane solution through hydrogen-bonding and π-π stacking interaction.

青蛤MAPK/p38基因的克隆及Poly:Ic胁迫下的表达分析

[目的]克隆青蛤MAPK/p38基因,并分析其在Poly:Ic胁迫下的表达情况。[方法]利用转录组测序获得青蛤MAPK/p38基因的序列信息,采用生物信息学软件分析该基因在近缘生物间的进化关系;利用巢式及荧光定量PCR技术克隆青蛤MAPK/p38基因的结构域序列,并在Poly:Ic胁迫后立即分析该基因在青蛤各组织中的表达情况以及血淋巴中的时序性表达情况。[结果]克隆得到青蛤MAPK/p38基因的结构域序列,分析发现该基因在物种进化中很保守,其在青蛤的血淋巴、肝脏、外套膜、闭壳肌和鳃中均有表达,其中在血淋巴中表达量最高,腮中表达量最低。Poly:Ic胁迫3 h后该基因的表达量达到最大值,与对照组差异极显著(P<0.01)。[结论]MAPK/p38基因所表达的产物是青蛤重要的免疫信号通路蛋白。

Synthesis of Poly(p-phenyleneethynylene)s with Crosslinkable End or Side Groups and Its Solid State Structure and Optical Properties Before and after Crosslinking

Two crosslinkable poly（p-phenyleneethynylene）s（PPEs）： poly[2,5-di（2＇-ethyl-hexyloxy）-1,4-phenylenecthynylene] with end-capped vinyl（PPE1） and poly[2,5-di（allyloxy）-1,4-phenyleneethynylene-2,5-di（2＇-ethyl-hexyloxy）-1,4-phenyleneethynylene]（PPE2） were synthesized. Via the thermal addition reactions of vinyl end groups of PPE1 and allyloxy side groups of PPE2, crosslinked polymers C-PPE1 and C-PPE2 were obtained, respectively. The two polymers were characterized by wide-angle X-ray diffraction（WXRD）, ultraviolet-visible（UV-Vis） absorption, and photoluminescence（PL）. The results indicate that in the solid state, the polymer chains of PPE1 were packed with a low degree of crystallinity because of the sterically hindered（2＇-ethyl-hexyl）oxy branched side chains, but, because of the introduction of allyloxy side chains, the polymer chains of PPE2 were packed in an order fashion with a high degree of crystallinity. Because of the high crosslinking density in C-PPE2, the formation of aggregates and excimer was hampered by the formed crosslinking network more effectively in C-PPE2 film than in C-PPE1 film.

Effect of Added Poly (vinyl pyrrolidone) during Condensation on Properties of Poly(p-phenylene terephthalamide)Pulp

Poly(p-phenylene terephthalamide)(PPTA)pulp was prepared by polycondensation of the p-phenylene diamine(PPDA)with terephthaloyl chloride(TPC)in the completely anhydrous solvent system of N-methyl pyrrolidone(NMP)having calcium chloride,in the presence of poly(vinyl pyrrolidone)(PVP)having a viscosity average molecular weight lower than 40 000.It was confirmed that the polycondensation could be accelerated,the inherent viscosity of the polymer could be increased,and the polymers could be fibrillated more easily by the addition of the PVP.FTIR and X-ray spectra proved that PVP had not combined into molecular chains of the resultant PPTA pulps.The morphology of the resultant pulps,the effect of viscosity average molecular weight,amount and adding mode of PVP on inherent viscosity,specific surface area,and mean length of the resultant pulps were discussed in detail.And the friction and wear properties of the compound reinforced by the resultant pulps were simply investigated.

CRYSTAL STRUCTURE AND MORPHOLOGY OF NASCENT SAMPLES OF SYMMETRIC AROMATIC POLYESTERS——Ⅰ.POLY(P-PHENYLENE TEREPHTHALATE)

The morphology and crytal structure of poly(p-phenylene terephthalate) (PPT), prepared by confined thin filmmelt (CTFMP) and solution (CTFSP) and bulk solution polymerization, were characterized by transmission electronmicroscopy, electron dimaction and molecular modeling. The unit cell is monoclinic (P2_1/a space group) with parameters a =7.89, b = 5.49, c = 12.65 A, α=γ= 90°, β=100.33°, density = 1.48 g/cm^3, the a, b and β values differing slightly from thosereported previously in the literature. A degree of variation in relative intensities of hk0 reflections in, apparently, untilted[001] ED patterns was observed from a given sample, suggesting some variation in molecular packing. ED evidence wasfound for a second phase, with [001] appearing the same as for phase Ⅱ of the related poly(p-oxybenzoate) (PpOBA)polymer. CTFMP crystals polymerized above 220℃ (up to 370℃) and CTFSP crystals polymerized at 300℃ consisted oflamellae 100-200 A thick.

SYNTHESIS OF POLYMERIC β-CYCLODEXTRIN SUPPORTED BY CROSSLINKED POLY(ACRYLAMIDE-co-VINYLAMINE)AND ITS CATALYSIS OF THE HYDROLYSIS OF p-NITROPHENYL ACETATE

Polymeric β-cyclodextrin (β-CD) supported by crosslinked poly(acrylamide-co-vinylamine) was synthesized as anartificial analog of hydrolytic enzyme and its catalysis of the hydrolysis of p-nitrophenyl acetate (p-NPA) was theninvestigated. The result showed that the polymer-supported β-CD could accelerate the hydrolytic reaction of p-NPA morequickly than β-CD itself and crosslinked poly(acrylamide-co-vinylamine) alone. The acceleration rate of the polymer-supported β-CD was about 10 times as fast as that of free β-CD in 0.01 mol/L phosphate buffer (pH 7.4) containing 32%DMSO at 37±0.1℃ when the molar amount of β-CD units in the polymer was equal to that of free β-CD in the experiments.The enhanced acceleration of thc polymer-supported β-CD should be ascribed to the cooperative contribution of theinclusion effect of β-CD ring and the nucleophilic effect of amino groups on the polymeric support.

PBO/PIPD纳米纤维复合薄膜的制备及性能研究

通过在聚对苯撑苯并二噁唑(PBO)纳米纤维基体中引入聚(2,5-二羟基-1,4-苯撑吡啶并二咪唑)(PIPD)纤维制备了PBO/PIPD纳米纤维复合薄膜,并利用Cu^(2+)的络合作用协同增强PBO/PIPD纳米纤维复合薄膜的交联结构。对所制备的PBO/PIPD纳米纤维复合薄膜进行了微观结构的表征以证实其3D网状交联结构,并对PBO/PIPD纳米纤维复合薄膜的结构与组成进行了研究。研究了不同金属离子和不同质量分数PIPD纤维对PBO/PIPD纳米纤维复合薄膜力学性能的影响。结果表明,相比于原始PBO纳米纤维薄膜,本文所制备的PBO/PIPD纳米纤维复合薄膜具有优异的力学性能。其拉伸强度提高了2.4倍达到100.99 MPa,断裂伸长率提高了8.5倍达到10.5%。

The Electroluminescence Characterization of Poly(p-phenyleneethynylene)——The π-conjugated Backbone Interrupted by a Butylene Unit

π -Conjugated poly( p -phenyleneethynylene) with the interruption of the conjugation by a butylene unit was synthesized. Its absorption, PL and EL spectra were investigated respectively. The spectral peaks shifted to the higher energy side with the interruption of the conjugation lengths. The model compound was synthesized, by which the results were proved. The thermal characteristics of the polymer was determined by DSC and TGA, indicating that the polymer has a good thermal stability. The electroluminescence(EL) in the green region of the spectrum with a maximum at 500 nm was observed from the polymer films sandwiched between indium-tin-oxide and an Al electrode.