制样方法对SiO2/PA6复合材料基体PA6结晶熔融行为的影响

采用差示扫描量热法(DSC)研究了原位聚合法和熔融共混法制样方法对纳米SiO2/PA6纳米复合材料结晶熔融行为的影响,结果表明:通过阴离子原位聚合法制备的纳米复合材料,由于采用超声波分散技术,纳米粒子在基体的分散性好。随着纳米粒子含量的升高,纳米粒子的诱导成核能力增强;熔融共混法制得复合材料中,SiO2在机械力的剪切作用下,很难均匀地分散,多以团聚体的形式存在,在PA6基体结晶时,结晶成核的条件相匹配,有较强的成核效应,纳米粒子的含量影响不大。     

高含量碳纤维对尼龙6非等温结晶与熔融行为的影响

利用差示扫描量热仪（DSC）研究了高含量碳纤维（CF）对尼龙6（PA6）非等温结晶与熔融行为的影响。结晶行为研究结果表明，高含量CF的引入对PA6的结晶起到异相成核作用，提高了PA6的总结晶速率。熔融行为研究结果表明在低的降温速率下。CF诱导基体尼龙6形成亚稳态的γ^＊结晶，其熔融峰为一个明显的不对称单峰；高降温速率下为熔融双峰，低温峰为亚稳态的γ^＊结晶的熔融。而高温峰为亚稳态的结晶在升温过程中发生再结晶和再组合形成更稳定的γ结晶的熔融。     

聚苯硫醚熔体结晶自成核作用的研究--聚苯硫醚多次扫描的熔体结晶行为

用差示扫描量热法多次扫描研究聚苯硫醚（PPS）在不同的熔融温度（Tmelt)以及交变温度熔融对其结晶行为的影响。结果表明：PPS的结晶温度（Tc) 随Tmelt提高而降低；但Tmelt低时，PPS的Tc随扫描次数增加而提高。随扫描次数增加，PPS呈现多结晶峰。同一试样交变温度熔融，低温熔融结晶的Tc总量比高温熔融结晶的Tc高，而且与扫描次数无关，归结于PPS的自成核作用。     

PA6与PA66共混物或共聚物的定性定量分析

采用裂解气相色谱-质谱联用法和差示扫描量热法建立了聚酰胺(PA)6/PA 66共混物或共聚物的定性定量分析方法。选取己内酰胺和环戊酮分别作为PA 6和PA 66的特征裂解产物,建立了PA 6在共混物或共聚物中的质量分数比与己内酰胺的峰面积比的线性回归方程,再结合熔点判断是共混物还是共聚物。结果表明:通过已知试样进行验证,定量偏差≤2%,能正确判断试样为共混物还是共聚物,该方法方便快捷,灵敏度和准确性高,对PA的成分分析具有指导意义。     

差示扫描量热法测量尼龙6熔融焓的不确定度评定

本文依据国家标准GB/T 19466.3-2004,采用差示扫描量热法(DSC)测量尼龙6(PA6)的熔融焓,讨论了测量过程中的不确定度来源并对测量不确定度进行评定,结果表明DSC测定PA6熔融焓的不确定度的结果为50.92J/g,u95=2.06J/g(4.0%)。     

不同测试方法对聚乙二醇差示扫描量热法曲线的影响

利用差动热分析仪在空气和氮气两种介质及不同升温方式下,测定聚乙二醇的熔融蜂温度(Tp)和熔融热焓(△H).研究表明:无论在哪种介质下,升温速率不同都会引起差示扫描量热法(DSC)曲线的变化,升温速率越大,Tp也越高;介质不同和升温方式不同也会引起DSC曲线的变化,空气对△H的影响较大;不同介质对热传导的不同会导致Tp有较大差异;在保护性气体下,可选择二次升温的方式以消除试样填装误差及热历史的影响.     

聚苯硫醚PPS结晶性能的影响因素分析

采用差示扫描量热法(DSC)研究了分子结构、熔融温度、熔融时间及剪切作用对聚苯硫醚(PPS)结晶性能的影响,并通过热台偏光显微镜研究了结晶过程中PPS的晶体形态变化.结果表明,两种PPS在结晶性能、结晶形态方面存在明显差异,相比Keji-PPS,Kureha-PPS在结晶时成核速率更快,且结晶温度更高;在同等物料状态下...     

聚苯硫醚PPS结晶性能的影响因素分析

采用差示扫描量热法(DSC)研究了分子结构、熔融温度、熔融时间及剪切作用对聚苯硫醚(PPS)结晶性能的影响,并通过热台偏光显微镜研究了结晶过程中PPS的晶体形态变化。结果表明,两种PPS在结晶性能、结晶形态方面存在明显差异,相比Keji-PPS,Kureha-PPS在结晶时成核速率更快,且结晶温度更高;在同等物料状态下,同一PPS粉末料和颗粒料的结晶温度和熔融温度也存在较大差别;熔融温度和熔融时间对Kureha-PPS的结晶性能影响较大,剪切对其结晶性能影响则较小;随着熔融温度的升高,其最大结晶温度下降,而随着熔融时间的增加,其最大结晶温度增大;Kureha-PPS在降温结晶过程中,所形成的球晶尺寸小而细密。     

TLCPa对PA 6/PA 66相容性及结晶行为的影响

采用溶液共混法制备了聚酰胺6(PA 6)／聚酰胺66(PA 66)/热致聚酰胺液晶(TLCPa)共混物,分析了TLCPa对PA 6／PA 66相容性及结晶行为的影响。差示扫描量热法分析表明,TLCPa的加入改善了PA 6和PA 66之间的相容性,PA 6／PA 66共混物结晶受到抑制;傅里叶变换红外光谱研究表明,TLCPa和PA 6、PA 66分子间形成了大量的分子间氢键,是TLCPa改善共混物相容性的主要原因;广角X射线衍射分析表明,TLCPa的加入没有影响共混物的晶型结构,当w(TLCPa)大于10％时,共混物的结晶度明显下降。     

不同增容剂对PP/PA6共混物性能的影响及其增容机理研究

采用多种增容剂对聚丙烯/聚酰胺6(PP/PA6)共混体系进行改性,包括：离子聚合物、马来酸酐接枝聚丙烯、聚乙烯-丙烯酸丁酯-马来酸酐共聚物等。对共混物进行扫描电子显微镜（SEM）、差示扫描量热法（DSC）以及断裂伸长率、低温断裂伸长率、耐磨性能测试和分析,讨论了不同种类增容剂的增容机理,探究了相容性对材料物理性能的影响。     

Multiple melting behavior of polyphenylene sulfide blends with polyamide 6

Although there are many studies on the multiple melting behavior of polyphenylene sulfide (PPS) homopolymer, similar investigations on PPS component in PPS blends with thermoplastics are relatively rare. In the present paper, the multiple melting behavior of PPS blends with polyamide 6 (PA6) have been investigated by differential scanning calorimetry (DSC). The double melting peaks are also observed for PPS in the blends. Although the annealing temperature and time as well as the heating rate of DSC scanning are different, the lower melting peak temperature of PPS in the blend is higher than that of pure PPS and the higher melting peak temperature is lower than that of pure PPS. It is suggested that PA6 can accelerate the cold‐crystallization of amorphous PPS due to the possible presence of interfacial interaction between the component polymers to induce the heterogeneous nucleation, and increase the perfection of PPS crystals. The multiple melting behavior of PPS in the blends are explained by recrystallization. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1579–1585, 2000     

Effect of blending on the multiple melting behavior of polyphenylene sulfide

The effects of melting time (t_melt) and annealing time (t_a) at a temperature closer to the melting point of polyphenylene sulfide (PPS) on the multiple melting behavior of neat PPS, and PPS component in their blends have been investigated by differential scanning calorimetry (DSC). It is found that double endotherm peak of PPS annealed at 275°C for less than three hours is different from that annealed for twelve hours. Double endotherm peak of PPS in PEEK/PPS blends shifts to lower temperature, and the intensity of the upper melting peak decreases significantly by addition of polyether ether ketone (PEEK). An additional third melting peak could be observed. The temperature of third melting peak is above 310°C and increases as the t_a and PEEK content are increased. For PEK-C/PPS blends, the lower and upper melting temperatures of the PPS component are higher than that of neat PPS annealed at 275°C for twenty-three hours. © 1996 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1001–1008, 1997     

聚苯硫醚的流变性能研究

采用毛细管流变仪研究了纤维级聚苯硫醚(PPS)的流变性能。结果表明,PPS在剪切速率为150～400s~(-1)时,会出现剪切增稠现象;剪切速率在400～1000 s~(-1)时,PPS熔体为假塑性流体,PPS的非牛顿指数随温度的升高而逐渐趋近于1,PPS熔体的表观粘度与温度之间的关系符合Arrhenius方程,PPS熔体的粘流活化能随剪切速率的增大而减小,减小的速度随剪切速率的增大而变慢。     

Nonisothermal crystallization of poly(phenylene sulfide) in presence of molten state of crystalline polyamide 6

The nonisothermal crystallization and melting behavior of a poly(phenylene sulfide) (PPS) blend with polyamide 6 (PA6) were investigated by differential scanning calorimetry. The results indicate that the crystallization parameters for PPS become modified to a greater extent than those for PA6 in the blends. The PPS and PA6 crystallize at high temperature as a result of blending. The crystallization temperatures of PPS in its blends are always higher than that of pure PPS and are independent of the melting temperature and the residence time at that temperature. The PPS crystallization peak becomes narrower and the crystallization temperature shifts to a higher temperature, suggesting a faster rate of crystallization as a result of blending with PA6. This enhancement in the nucleation of PPS could be attributed to the possible presence of interfacial interactions between the component polymers to induce heterogeneous nucleation. On the other hand, the increase in the crystallization temperature of PA6 can be attributed to the heterogeneous nucleation provided by the already crystallized PPS. The heterogeneous nucleation induced by interfacial interactions depends on the temperature at which the polymers remain in the molten state and on the storage time at this temperature. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3033–3039, 1999     

Effects of polyphenylene oxide content on morphology,thermal, and mechanical properties of polyphenylene oxide/polyamide 6 blends

A series of composites of PPO/PA 6 with improved toughness were synthesized by using ε‐caprolactam as a reactive solvent. Inserting minor PPO macromolecules (1–3 wt %) into PA 6 matrix obviously reduced the crystallinity of PA6. Two crystallization temperatures were found when 6 wt % PPO was added. SEM revealed that the phase morphology of the composites could be manipulated by varying the content of PPO in PA 6. As a consequence, the impact strength and the elongation of PPO/PA6 were improved with maintenance of tensile strength when quite small content of PPO (1–3 wt %) was incorporated. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

聚苯硫醚合成技术及其应用

介绍了聚苯硫醚(PPS)的物理化学性能,分析了硫化钠法、硫磺溶液法、硫化氢法、对卤代苯硫酚缩聚法和氧化聚合法合成PPS的技术;阐述了PPS的应用进展;详述了PPS的成形与加工技术研究;PPS具有优异的热稳定性、耐化学腐蚀性、阻燃性等,在环保、电子、机械、汽车、纺织、航空航天等领域中得到广泛应用;提出加快高性能PPS合成与加工的研发力度,促进PPS纤维纺丝技术研究及工业化的应用。     

Influence of fibrillated poly(tetrafluoroethylene) on microcellular foaming of polyamide 6 in the presence of supercritical CO2

In this article, PA6/poly(tetrafluoroethylene) (PTFE) composites were prepared by internal mixer with high rotor speed. The existence of PTFE nano-fibrillation network structure was observed by scanning electron microscopy (SEM) analysis. The effect of PTFE on crystallization and rheological behavior of PA6 was evaluated. The result showed that the PTFE fibrils improved the crystallization properties of PA6 and do not change the crystal structure. The PTFE effectively enhanced the melt strength of PA6 by fibrillation. The PA6/PTFE composites were then foamed assisted by supercritical CO₂. The PTFE was used as cell nucleating agent, crystal nucleating agent and melt strength enhancement agent in the foaming process. Finally, the microcellular PA6 foams were successfully obtained with the cell density higher than 10⁹ cells/cm³, the cell size of ca. 14 μm and the volume expansion ratio of 16.     

聚苯硫醚单丝的制备

聚苯硫醚(PPS)单丝是一种新型的高性能纤维,具有很好的耐化学稳定性和耐热稳定性.阐述了PPS单丝制备的工艺过程,研究了原料及其干燥和纺丝温度、喷丝板规格、牵伸温度与倍数、热定型温度对PPS单丝性能的影响.结果表明,选择可纺性良好且干燥后含水率低于50μg/mL的切片,孔径为2 mm和长径比为1:5的喷丝板,一级牵伸温...     

Effect of high-performance polymers on crystallization and multiple melting behavior of poly(phenylene sulfide)

The crystallization and multiple melting behavior of poly(phenylene sulfide) (PPS) and its blends with amorphous thermoplastic bisphenol A polysulfone (PSF) and phenolphthalein poly(ether ketone) (PEK-C), crystalline thermoplastic poly(ether ether ketone) (PEEK), and thermosetting bismaleimide (BMI) resin were investigated by a differential scanning calorimeter (DSC). The addition of PSF and PEK-C was found to have no influence on the crystallization temperature (T_c) and heat of crystallization (ΔH_c) of PPS. A significant increase in the value of T_c and the intensity of the T_c peak of PPS was observed and the crystallization of PPS can be accelerated in the presence of the PEEK component. An increase in the T_c of PPS can also be accelerated in the BMI/PPS blend, but was no more significant than that in the PEEK/PPS blend. The T_c of PPS in the PEEK/PPS blends is dependent on the maximum temperature of the heating scans and can be divided into three temperature regions. The addition of a second component has no influence on the formation of a multiple melting peak. The double melting peaks can also be observed when PPS and its blends are crystallized dynamically from the molten state. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 637–644, 1998