PTT／纳米CaCO3复合材料流变行为及结晶性能研究

以毛细管流变仪研究了聚对苯二甲酸丙二酯(PTT)/纳米CaCO3复合材料的流变行为,讨论了复合材料的组成、剪切应力和剪切速率及温度对熔体流变行为、熔体黏度的影响,测定了不同配比的复合材料熔体的非牛顿指数 n。结果表明,PTT/纳米CaCO3复合材料熔体为假塑性流体,表观黏度随着剪切速率增加而降低。纳米CaCO3的加入量较少(1％)时,熔体黏度较纯PTT迅速下降;随着纳米CaCO3含量增加(2％-20％),熔体黏度随之上升,但都小于纯PTT的;直到含量为30％时,熔体黏度才超过纯PTT的。差示扫描量热仪测定复合材料的结晶和熔融性能发现,复合材料的熔体结晶温度Tpc和熔融温度Tm较纯PTT、都有所升高,说明纳米CaCO3的加入对PTT的结晶起到了异相成核作用。     

HDPE/石墨导热复合材料流变行为研究

制备了高密度聚乙烯(HDPE)/石墨导热复合材料,研究了该复合材料在毛细管流变仪中的流变行为。结果表明:该HDPE/石墨复合材料熔体在毛细管流变仪中的流动为非牛顿型流动,遵从假塑性流体的流动规律。随着石墨用量的增加,复合材料熔体的真实黏度、黏流活化能增大,非牛顿指数呈减小的趋势;随着剪切速率的增加,复合材料熔体的真实黏度和黏流活化能则均有所减小;而随着温度的升高,复合材料熔体的非牛顿指数呈增大的趋势。     

PET-PTT共聚酯的流变性能

利用毛细管流变仪研究了聚对苯二甲酸乙二酯(PET)-聚对苯二甲酸丙二酯(PTT)共聚酯(简称PETT)熔体的剪切流动性能,且与对应纯组分的流变性能进行了比较.结果表明:PETT熔体属于非牛顿流体,在相同温度下,PETT的剪切速率和黏度均小于纯PTT的值,且均随PTT链段含量的增加而减小.PETT的非牛顿指数和结构黏度指数均小于纯PTT.在相同剪切速率下,PETT的黏流活化能介于纯PET和纯PTT之间,且随PTT链段含量的增加而减小.     

mLLDPE/EPPE共混体系的流变行为、结晶形态与力学性能研究

研究了不同比例共混的茂金属线性低密度聚乙烯(mLLDPE)和易加工聚乙烯(EPPE)熔体的流变学行为,讨论了共混物组成,剪切速率和剪切应力以及温度对熔体流变曲线,熔体黏度和非牛顿指数的影响。结果表明:随着EPPE含量的增加,共混熔体的黏度呈线性下降,非牛顿指数逐渐减小,黏流活化能先升高后下降,mLLDPE的流动性和加工性能得到改善,而力学性能显示:EPPE在改善mLLDPE流变加工性能的同时可以很好保持mLLDPE的优良性能。     

PP-g-MAH增容PP/玻纤增强PA6共混体系流变性能研究

采用毛细管流变仪,以聚丙烯接枝马来酸酐(PP-g-MAH)为增容剂,研究了PP-g-MAH对PP/玻纤增强聚酰胺6(PA6)共混体系流变性能的影响。结果表明:PP/玻纤增强PA6共混体系为典型的切力变型流体,共混体系的表观黏度均随着剪切速率的增大而降低;随增容剂用量的增加,共混体系的表观黏度提高,非牛顿指数n先增大后减小,黏流活化能ΔEη和结构黏度指数Δη先减小后增大;增容剂用量为5%时,共混体系的非牛顿指数出现极大值,黏流活化能和结构黏度指数出现极小值。     

PA6/MXD6/黏土复合材料的流变行为研究

采用毛细管流变仪研究了聚己二酰间苯二甲胺(MXD6)及黏土的引入对聚酰胺6(PA6)流变性能的影响。结果表明:PA6、PA6/黏土、PA6/MXD6和PA6/MXD6/黏土复合材料均为假塑性流体;在220~240℃之间,PA6及其复合材料的非牛顿指数为0.50~0.85。另外,加入黏土使得PA6和PA6/MXD6的黏度上升,非牛顿指数和黏流活化能下降;而加入MXD6则使得PA6、PA6/黏土的黏度下降,非牛顿指数和黏流活化能上升。     

PTT/PP-g-MAH/PP共混材料形态和流变性能研究

以毛细管流变仪和扫描电子显微镜研究了聚对苯二甲酸丙二醇酯(PTT)/聚丙烯接枝马来酸酐(PP-g-MAH)/聚丙烯(PP)共混体系的形态和流变行为。讨论了共混物的组成、增容剂含量对共混物的形态、熔体流变行为的影响。结果表明:PP-g-MAH改善了PP与PTT的相容性,PP在PTT连续相中分散均匀,分散相尺寸随着增容剂含量的增加而减小。共混物熔体为假塑性流体,其非牛顿指数n、熔体黏度、黏流活化能随增容剂含量的增加而降低。     

PTT/MMT复合材料流变性能的研究

采用熔融共混法制备了聚对苯二甲酸丙二酯/蒙脱土（PTT/MMT）复合材料,并采用毛细管流变仪对复合材料的流变性能进行了研究。结果表明,PTT和PTT/MMT复合材料均为假塑性流体,1 %~3 %的MMT就可以显著改善复合材料的流动性。复合材料的非牛顿指数大于PTT,表观黏度小于PTT,流动性优于PTT,可以在较低的温度下成型加工;复合材料的黏流活化能高于PTT,更适合通过升高温度的方法来改善其流动性。     

三羟甲基丙烷改性共聚酯的结晶性能和流变行为

采用直接酯化熔融缩聚法合成了一系列不同含量的三羟甲基丙烷(TMP)改性共聚酯(BPET),并对其基本物性参数、结晶性能和流变行为进行了表征。结果表明,TMP加入量为1.536 %(摩尔百分含量,下同)时,BPET的特性黏度和相对分子质量明显提高;随TMP含量的增多,BPET的半结晶时间延长,熔融结晶峰温降低;随TMP含量的增大,BPET熔体的非牛顿指数变小,偏离牛顿流体的程度变大,表观黏度对切变速率的依赖性增强;在实验切变速率下,BPET的黏流活化能均低于均聚对苯二甲酸乙二醇酯(LPET)的黏流活化能,BPET不适合使用升高温度的方法来改善其流动加工性能。     

聚丙烯/纳米羟基磷灰石复合材料流变性能研究

采用毛细管流变仪对聚丙烯/纳米羟基磷灰石(PP/n HA)复合材料的流变性能进行了研究,并讨论了复合材料的表观黏度、非牛顿指数、黏流活化能与温度、剪切速率、n HA用量之间的关系。结果表明:PP/n HA熔体为假塑性流体,其表观黏度随着n HA用量的增加总体呈上升趋势,但在其用量为1%时达到极小值;非牛顿指数随着温度的提高而增大,随着n HA用量的增加而逐渐减小;黏流活化能则随着剪切速率的增加逐渐降低,随着n HA用量的增加呈上升趋势。     

相容剂对玻纤增强尼龙6流变行为的影响

通过熔融挤出制备了含有不同用量相容剂马来酸酐接枝线性低密度聚乙烯（LLDPE-g-MAH）和硅烷偶联剂的玻璃纤维（GF）增强尼龙6（PA6）复合材料，并用毛细管流变仪研究了复合材料的流变行为，得到了熔体流变性能关系曲线。结果表明，不管是否存在硅烷偶联剂，PA6／GF／相容剂复合材料的流变行为符合假塑性流体的流动规律，非牛顿性比PA6／GF强，表观粘度随温度升高和剪切速率的增加而降低。随着相容剂用量的增加，复合材料的表观粘度不断增大，而非牛顿指数变小，而且流动活化能变小。     

Preparation,structure, and properties of the PTT/SGF composites

Short glass fiber reinforced poly(trimethylene terephthalate) composites (PTT/SGF) were prepared by twin screw extruder. The structural feature and physical properties of these composites were studied by scanning electron microscope, differential scanning calorimetry, thermalgravimetric analyzer, capillary rheometer, universal tester, etc. The glass fiber was modified by the silane coupling agent before being blended with the polymer. The results suggest that there is strong interaction between SGF and PTT matrix, which leads to an increasing on the tensile strength, Young's modulus, impact strength and thermal stability of the composites with proper contents of SGF. Rheological behavior of the PTT/SGF composites melt is complicated, combining a dilate fluid at lower shear rate and a pseudo-plastic fluid at higher shear rate. The melt apparent viscosity of composites decreases with increasing SGF content because of the rigid fibers improving the flow of the melt. Moreover, the flow activation energy of the composites suggests that the melt with more SGF has lower sensitivity to the processing temperature. In conclusion, the composite with 10–20 wt% content of SGF has better properties. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

表面处理纳米铜粉/PET共混物的流变性能

采用硅烷偶联剂KH-550对纳米铜粉进行表面处理,通过熔融共混制备纳米铜粉/PET共混物,用毛细管流变仪研究了共混物的流变性能。结果表明:纳米铜粉/PET共混体系为非牛顿性假塑性流体,其表观黏度随着剪切速率的增大而减小;随着纳米铜粉含量增加,非牛顿指数增大;共混物的黏流活化能随剪切速率的增加而减小。     

简单剪切流场中PTT熔体的流变性能研究

研究了PTT熔体在简单剪切流场中的流变性能。结果表明,PTT熔体是典型的切力变稀型非牛顿流体,剪切流动符合幂律定律;随温度提高,熔体的△_η减小,但热降解增加;在相同γ下,相对分子质量增大,将使熔体的σ、η_a和△_η增大,n减小;PTT熔体的E_η值高于PET,且γ增大E_η值减小;n对T和γ有明显的依赖性,T提高n线性增大,而γ增大n明显减小,所以计算n时不能取其γ范围内的算术平均值,而应该取其微分值。     

玻璃纤维增强HDPE熔体流变性能研究

采用毛细管式流变仪研究了不同温度条件下玻璃纤维（以下简称玻纤）增强ＨＤＰＥ复合材料熔体的流变性能，及其与材料界面粘结性、玻纤含量等的关系。实验结果表明：材料界面粘结强度越大，玻纤含量越高，熔体表观粘度对温度的敏感性减弱，对剪切速率的敏感性则增强。对该类材料的成型应选择稍高的加工温度及剪切速率较为适宜。     

Effects of coupling agents on the rheological properties,processability, and mechanical properties of filled polypropylene

An experimental study was carried out to investigate the effects of coupling agents on the rheological properties, processability, and mechanical properties of highly filed polypropylenes (PP). Inorganic fillers used were CaCO₃ and glass beads, and coupling agents used were two silane coupling agents, N-octyl triethoxy silane and γ-aminopropyl triethoxy silane, and one titanate coupling agent, isopropyl triisostearoyl titanate. It was found that the addition of the coupling agents to the PP-CaCO₃ (50 wt percent) decreased the melt viscosity and increased the melt elasticity (first normal stress difference). However, the addition of the silane coupling agents to the PP-glass beads (50 wt percent) affected the rheological properties of the melts quite differently. The N-octyl triethoxy silane had relatively little effect on either the melt viscosity or the melt elasticity, whereas the γ-aminopropyl triethoxy silane increased the melt viscosity and decreased the melt elasticity. The CaCO₃- or glass bead-filled polypropylenes, with and without coupling agents, were injection-molded and the mechanical properties of the molded specimens were measured by the use of an Instron testing machine. It was found that the effect on the tensile strength and percent elongation of the filled polypropylenes depended upon the specific coupling agent utilized. A melt-spinning study was also carried out to investigate the effect of coupling agents on the spinnability (defined as the maximum draw-down ratio) of the PP-CaCO₃ system, and on the mechanical properties of the melt-spun fibers. It was found that the spinnability of the PP-CaCO₃ was enhanced considerably by the addition of the coupling agents, and that the tensile strength of the melt-spun fibers was also improved by their addition. Scanning electron micrographs were taken of the fracture surface of injection-molded specimens and an attempt was made, with the aid of photomicrographs, to explain the mechanical properties of molded specimens observed experimentally.     

Effects of coupling agents on the rheological behavior and physical/mechanical properties of filled nylon 6

An investigation was made on the rheological behavior and physical/mechanical properties of highly filled nylon 6 composites with and without a coupling agent. As fillers, calcium carbonate and calcium silicate were used, and, as coupling agent, two silanes (Union Carbide, A1100 and Y9187) and two titanates (Kenrich Petrochemicals, KR-44 and KR-138) were used. It was found that all the coupling agents used increased the viscosities of the nylon/CaCO₃ system. However, the effect of the coupling agents on the viscosity of the nylon/CaSiO₃ system seems quite complex; namely, the titanate KR-44 decreased the melt viscosity of the nylon/CaSiO₃ composite, whereas the titanate KR-138S and the silane Y9187 increased it. In general, the effectiveness of the coupling agents in improving the physical/mechanical properties of the nylon/CaCO₃ and nylon/CaSiO₃ composites was marginal. A considerable decrease in glass transition was observed upon exposure of all samples to water, regardless of the type of filler and coupling agent.     

尼龙11/空心玻璃微珠复合材料流变行为研究

采用XLY–Ⅱ型毛细管流变仪研究了尼龙(PA)11/空心玻璃微珠(HGB)复合材料的流变行为。结果表明,PA11/HGB复合材料熔体为假塑性流体,呈现出剪切变稀的行为。随HGB含量的增加,复合材料的表观黏度和粘流活化能总体上增大,这表明复合材料熔体对温度敏感性较大。     

TiO_2/ZnO超细粉体共混改性PET的流变性能

将改性的二氧化钛/氧化锌(TiO2/ZnO)超细复合粉体应用于聚对苯二甲酸乙二醇酯(PET)的共混改性,研究了改性PET的流变性能及其纤维的力学性能。结果表明:改性PET共混物为非牛顿假塑性流体,其表观粘度随剪切速率的增大而减小;随着超细粉体含量增大,改性PET共混物非牛顿流动指数下降,熔体粘度对温度的敏感性增大,流变性能改善;当超细粉体质量分数为5%时,改性PET共混物粘流活化能可达81.5 kJ/mol;随着超细复合粉体添加量增大,改性PET纤维断裂强度下降。