PC/UHMWPE共混物的流变性能

采用熔融共混的方法 ,制备了两种不同配比的PC/UHMWPE共混物。采用毛细管流变仪和熔融指数仪研究了PC/UHMWPE共混物的流变行为 ,结果表明 :PC/UHMWPE共混物熔体的流变行为呈假塑性流体的特征 ,表观粘度随剪切速率的增加而减小 ,随温度的升高而降低 ;共混物熔体的粘度大于纯PC的粘度。采用悬浮体系模型讨论了两种共混物的流变行为     

苯乙烯-马来酸酐无规共聚物的研究进展

介绍苯乙烯(St)-马来酸酐(MAH)无规共聚物(R-SMA)的发展历程和聚合机理,分析R-SMA合成的影响因素,总结近年来R-SMA的主要聚合方法,并对R-SMA的未来发展进行展望。MAH与St极易进行交替聚合,可以通过提高温度和加入极性溶剂抑制交替聚合倾向,以合成R-SMA。溶液聚合法R-SMA具有传热效率高、可控性好的优点。在极性溶剂选择上,选择一种或多种混合环保型溶剂代替传统有机溶剂是需要解决的问题。     

PEEK/PEI共混物的相容性和结晶行为研究

在380℃下熔融挤出制得聚醚醚酮（PEEK）与聚醚酰亚胺（PEI）共混物。采用差示扫描量热仪（DSC）和广角X射线衍射仪（WAXD）研究了共混物的相容性和结晶行为。结果表明，PEEK／PEI共混物完全相容．所有共混物均呈现一个玻璃化转变温度（Tg），且与组分的关系符合Porch方程；随PEI含量的增加，共混体系的熔点、结晶度、整体结晶速率和结晶能力均降低：而PEEK的结晶度呈现先增加后减小的趋势，当PEI质量分数为50％时，达到最大。     

共混物PBS/PPC/MPEG的断裂力学及其热降解性能研究

采用熔融共混法制备了PBS/PPC/MPEG(WMPEG=0%,5%,10%,15%,20%)共混物,利用单边缺口弯曲试验(SENB)研究了MPEG用量对其断裂的临界能量释放率Gin的影响;以热重分析法(TG)研究了PBS/PPC及PBS/PPC/MPEG在氮气气氛中的热降解过程,并采用Kissinger法研究了共混物的热降解动力学和表观活化能(E)。结果表明:当MPEG含量为5%时,共混物临界能量释放率Gin达到最大值1.47 kJ/m2;共混物出现两个热失重峰,热降解活化能为125.5 kJ/mol,增容剂MPEG的引入,使共混物的活化能提高了到160.1 kJ/mol。     

相容剂对TPEE/LDPE共混材料的结构及性能影响研究

采用熔融挤出的方法将热塑性聚醚酯弹性体(TPEE)、低密度聚乙烯(LDPE)、乙烯醋酸乙烯共聚物(EVA)共混,固定EVA与TPEE质量比,制备了一系列不同TPEE含量的TPEE/LDPE共混物,研究了EVA对TPEE/LDPE共混物力学性能和形态变化的影响。结果表明当TPEE含量为10%时,相容剂EVA改性后的共混物力学性能最佳,拉伸强度为10.8MPa,断裂伸长率为508.5%;TPEE颗粒的尺寸更小,且分布更均匀。     

超支化聚（酰胺-酯）／ABS／聚氯乙烯共混体系相容性研究

研究了超支化聚(酰胺-酯)(HBP)对ABS/聚氯乙烯(ABS/PVC)共混体系的增容作用。讨论了HBP用量对ABS/PVC(80/20)和相同量HBP对不同比例ABS/PVC力学性能的影响。实验结果表明ABS/PVC共混物中加入HBP,可以有效改善共混体系的相容性;加入2份HBP时,ABS/PVC(80/20)共混物拉伸强度达到最大值,继续增加HBP,共混物拉伸强度快速下降,而共混物冲击强度单调下降;不同比例ABS/PVC中加入2份HBP共混物拉伸强度比未加入HBP共混物拉伸强度增加,但共混物冲击强度减小。扫描电子显微镜研究结果证明了HBP增强了ABS/PVC的界面黏结作用,减小了共混体系的相分离程度。     

PLA/PEO共混物的结晶行为研究

共沉积技术制备了聚乳酸(PLA)/聚氧化乙烯(PEO)共混物,通过DMA和相差显微镜考察了共混物的相行为。用DSC研究了PLA/PEO共混物的结晶形貌及其动力学,由于部分相容的熔融态PEO提高了PLA分子链的运动能力,导致显著促进了PLA的结晶速率;结合偏光显微镜(POM)观察分析,结晶速率的提高源于结晶生长速率的促进,而且在低的结晶温度时的结晶速率的增加更为明显。     

不同分子量PCL增韧PLA的结构与性能

采用两种不同分子量的聚(ε-己内酯)(PCL)(粘均分子量60 000和3 000)与聚乳酸(PLA)在175℃下共混10 min制备PLA/PCL共混物。通过动态流变、扫描电子显微镜(SEM)和力学性能等研究了PLA/PCL共混物的结构和性能。动态流变显示,在PCL低含量(质量分数小于15%)时,PCL与PLA是相容的,质量分数为15%时PCL与PLA表现出明显的相分离行为。SEM显示,随着PCL含量的增加,PCL相的尺寸变大;低分子量PCL(L-PCL)的相尺寸明显大于高分子量PCL(H-PCL),而且相形态不是规则的球状。随着PCL含量的增加,共混物的拉伸强度下降,而断裂伸长率增加。当H-PCL质量分数为8.3%时,PLA/H-PCL共混物的断裂伸长率为137.32%。当H-PCL质量分数为15%时,其断裂伸长率高达232.76%。在添加相同含量PCL时,PLA/H-PCL共混物的拉伸强度高于PLA/L-PCL;而PCL质量分数8%时,共混物的断裂伸长率相差不多,当PCL质量分数大于8%时,PLA/H-PCL共混物的断裂伸长率明显比PLA/L-PCL共混物的高。     

纤维素/聚乙二醇共混物中组分比例的变化对共混物Tg的影响规律及模型

应用DSC方法和经典的高分子共混物经验方程估算了纤维素/聚乙二醇共混物的玻璃化转变温度(Tg),并研究了Tg与两组分比例之间的关系。结果显示:该共混物的Tg随纤维素比例增加而降低,且明显低于两个独立组分的Tg,其规律为:Tg=A-B×Ln(WCell/WPEG)。与文献介绍的一些经典的高分子共混物Tg估算公式,如:Fox方程、Gordon-Taylor方程和Kwei方程相比较发现,其中惟有Fox方程似乎比较接近DSC实验导出的模型。     

绿色溶剂中苯乙烯-马来酸酐无规共聚物的合成及表征

使用绿色溶剂碳酸二甲酯(DMC)代替传统溶剂丙酮,在120℃、苯乙烯与马来酸酐配比为9:1及氮气环境下,以溶液聚合法制备了苯乙烯-马来酸酐无规共聚物(R-SMA),通过红外光谱、核磁共振、化学滴定等表征方法确证产物为R-SMA,并研究了两种溶剂及其用量对R-SMA组成、结构、分子量、转化率等的影响。结果表明:DMC作溶剂时,R-SMA以苯乙烯作为分子主链,其中SSM、MSS、MSM三种结构在分子链中随机分布,呈无规排列;随着DMC用量的增加,R-SMA的分子量降低,转化率先升高后降低,马来酸酐含量变化不大;与丙酮作溶剂相比,DMC作溶剂时,产物的分子量及马来酸酐含量均较低,耐热性更好。     

R-SMA共聚树脂及其改性研究

本文介绍了无规苯乙烯—马来酸酐共聚树脂（Ｒ—ＳＭＡ）的合成工艺、特性和用途，并叙述了Ｒ—ＳＭＡ改性研究状况．     

R—SMA共混合金的研究进展

无规苯乙烯-马来酸酐共聚树脂(R-SMA)可作为塑料合金中提高耐热性、易加工性等性能的树脂组分,其本身又是塑料合金的相容剂,且具有成本低的优势。本文较详细地介绍了R-SMA与PVC、ABS、聚碳酸酯(PC)、聚酰胺(PA)、聚对苯二甲酸丁二醇酯(PBT)等通用及工程树脂的塑料合金的技术进展。     

R-SMA树脂的合成工艺

介绍了普通型和抗冲型两类苯乙烯—马来酸酐无规共聚物（R－SMA）的合成工艺。在对比溶液、本体—悬浮、本体三种聚合方法的优、缺点之后，详细叙述了本体法的特点，包括典型配方、工艺条件以及聚合流程，浅析了GPPS／HIPS装置转产R—SMA的可行性。     

Semicontinuous thermal bulk copolymerization of styrene and maleic anhydride: Experiments and reactor model

Thermal bulk copolymerization of styrene (St) and maleic anhydride (MAH) has been carried out at 110–130°C and up to around 55 wt % conversion in a stirred tank reactor with an anchor impeller to prepare the random copolymer of St–MAH (R-SMA). A series of experiments in semicontinuous monomer adding process were done to investigate the effects of operating condition on monomer conversion, copolymer composition, and its uniformity. It has been shown that a random copolymer with constant composition can be obtained by semicontinuous copolymerization. A reactor model was developed to simulate the copolymerization processes. The numerical method in which the gel effect on the copolymerization is incorporated has exhibited excellent agreement between the model calculation and the experimental data. However, when using the assumption that (1) k₂₂ = 0; (2) k₂₁[M₁] ≫ k₁₂[M₂]; and (3) (R₁/2k_t)^1/2 is a constant, an analytical solution to the model was found to be available also. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1905–1912, 1998     

荧光光谱法研究二氢卟吩e6和锌二氢卟吩e6与牛血清白蛋白的相互作用

应用紫外光谱和荧光光谱法研究二氢卟吩e6(Ce6)和锌二氢卟吩e6(ZnCe6)分别与牛血清白蛋白(BSA)的相互作用。通过紫外光谱、荧光光谱、光照实验,探讨了两种物质与BSA相互作用的荧光猝灭光谱特征、猝灭机理、与BSA结合反应及光照的影响。结果表明,Ce6和ZnCe6都可与BSA发生相互作用,Ce6和ZnCe6浓度的变化会引起Ce6、ZnCe6与BSA之间能量转移的变化,Ce6的猝灭程度要比ZnCe6强,猝灭机制是由静态猝灭引起的。Ce6与BSA的结合能力强于锌二氢卟吩e6,结合位点数均接近1,结合的作用力类型主要为范德华力和氢键作用力。Ce6-BSA和ZnCe6-BSA复合物均有光漂白特性,光漂白机制均为光学修饰型引起的,这种机制有利于提高光动力治疗(PDT)效果。     

纳米载银磷酸锆的有机改性及其对3D打印的义齿基托复合材料性能的影响

以γ甲基丙烯酰氧基丙基三甲氧基硅烷偶联剂(MPS)对纳米载银磷酸锆(6S-NP3)进行表面改性,再通过溶液聚合在其表面接枝甲基丙烯酸甲酯(MMA),得到有机改性纳米载银磷酸锆(P-6S-NP3)。将P-6S-NP3与义齿基托树脂混合,通过3D打印制备了义齿基托复合材料。使用傅里叶变换红外光谱仪(FT-IR)和扫描电镜(SEM)对改性前后6S-NP3的结构和形貌进行了表征,考察了6S-NP3和P-6S-NP3在义齿基托复合材料中的分散情况,测试了改性前后6S-NP3的水接触角、粒径分布,以及义齿基托复合材料的机械性能和抑菌性能。结果表明,MPS和MMA已成功接枝到6S-NP3表面,改性后的6S-NP3平均粒径降低,疏水性增强,在义齿基托复合材料中的分散性更好。采用P-6S-NP3制备的义齿基托复合材料的机械性能与对大肠杆菌和金黄色葡萄球菌的抑菌效果明显提高。     

层状铌基复合氧化物固体酸及其醋酸正丁醇酯化的催化活性

采用固相法合成出具有典型层状结构的LiNbMoO<,6>、LiNbWO<,6>和KTiNbO<,5>,并通过离子交换法获得HNbMoO<,6>、HNbWO<,6>和HTiNbO<,5>.采用X-射线粉末衍射(XRD)、扫描电镜(SEM)、NH<,3>程序升溢热脱附(NH<,3>-TPD)等技术对其进行表征.通过醋酸与正...     

Isothermal crystallization kinetics and melting behavior of multiwalled carbon nanotubes/polyamide‐6 composites

Pristine and functionalized multiwalled carbon nanotubes (MWNTs) were used to fabricate polyamide 6 (PA6) composites through melt blending. The functionalized MWNTs were obtained by grafting 1,6‐hexamethylenediamine (HMD) onto the pristine MWNTs to improve their compatibility with PA6 matrix. The effect of MWNTs on the isothermal crystallization and melting behavior of PA6 was investigated by differential scanning calorimetry (DSC) and X‐ray diffraction (XRD). The Avrami and Lauritzen–Hoffmann equations are used to describe the isothermal crystallization kinetics. The values of the Avrami exponent found for neat PA6, the pristine MWNTs/PA6 and functionalized MWNTs/PA6 composite samples are about 4.0, 1.7, and 2.3, respectively. The activation energies are determined by the Arrhenius method, which is lower for the composites, ?320.52 KJ/mol for pristine MWNTs/PA6 and ?293.83 KJ/mol for functionalized MWNTs/PA6, than that for the neat PA6 (?284.71 KJ/mol). The following melting behavior reveals that all the isothermally crystallized samples exhibit triple melting endotherms at lower crystallization temperature and double melting endotherms at higher crystallization temperature. The multiple melting endotherms are mainly caused by the recrystallization of PA6 during heating. The resulting equilibrium melting temperature is lower for the composites than for neat PA6. In addition, polarizing microscopy (PLM) and small angle light scanning (SALS) were used to study the spherulite morphology. The results show that the MWNTs reduce the spherulite radius of PA6. This reduction is more significant for pristine MWNTs. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

退火处理对PA6共混改性材料力学性能的影响

制备了玻璃纤维(GF)增强尼龙6(PA6/GF)、GF和马来酸酐接枝(乙烯/辛烯)共聚物(MAH-g-POE)增强增韧PA6(PA6/GF/MAH-g-POE),研究了不同退火温度和退火时间对PA6改性材料力学性能的影响.结果表明,PA6的力学性能与退火工艺有很强的关联性,添加GF和MAH-g-POE共混改性后,材料力学性能对退火工艺的依赖性仍然比较强,选择合适的退火工艺条件可以改善材料的力学性能.     

Compatibilizing effect of maleated polypropylene on the mechanical properties and morphology of injection molded polyamide 6/polypropylene/organoclay nanocomposites

Polyamide 6/polypropylene (PA6/PP=70/30 parts) blends containing 4 phr (parts per hundred resin) of organophilic modified montmorillonite (organoclay) were prepared using twin screw extruder followed by injection molding. Maleated polypropylene (MAH-g-PP) was used to compatibilize the blend system. The mechanical properties of PA6/PP nanocomposites were studied through tensile and flexural tests. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to assess the fracture surface morphology and the dispersion of the organoclay, respectively. X-ray diffraction (XRD) was used to characterize the formation of nanocomposites. The thermal properties were characterized by using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The dynamic mechanical properties of PA6/PP nanocomposites were analyzed by using dynamic mechanical thermal analyzer (DMTA). The strength and stiffness of PA6/PP nanocomposites were improved significantly in the presence of MAH-g-PP. This has been attributed to the synergistic effect of organoclay and MAH-g-PP. The MAH-g-PP compatibilized PA6/PP nanocomposites showed a homogeneous morphology supporting the compatibility improvement between PA6, PP and organoclay. TEM and XRD results revealed the formation of nanocomposites as the organoclay was intercalated and exfoliated. A possible chemical interaction between PA6, PP, organophilic modified montmorillonite and MAH-g-PP was proposed based on the experimental work.