BOPP烟膜树脂的结晶行为及性能

采用差示扫描量热仪和广角X-射线衍射仪研究了3种双向拉伸聚丙烯烟膜专用树脂的热性能、结晶行为。结果表明:F280T的结晶度、晶粒尺寸和结晶活化能明显小于试样1和试样2;在等温结晶条件下,3个试样的总结晶速率常数和总结晶速率随结晶温度的增加而下降,而半结晶时间增加;在研究温度范围内,所有试样的Avrami指数为2～3,且均为非整数;在结晶温度相同时,总结晶速率大小依次为试样1,F280T,试样2。     

PP吹塑薄膜专用树脂的结构与性能

分析测试了聚丙烯吹塑薄膜专用树脂F1608的综合性能及微观结构,并研究其加工流变性能及薄膜性能。结果表明,F1608具有与进口树脂相近的相对分子质量及其分布,较高的分子链规整度,分子结构合理。F1608的熔融温度、熔融热焓及结晶热焓与进口树脂接近,其力学、光学、加工等综合性能优良。流变及加工性能研究表明,F1608具有适当的熔体强度和最大牵伸速率,熔体弹性适中、黏度低、加工能耗小,薄膜成型性能好。     

熔喷专用聚丙烯树脂的研发和性能表征

以均聚聚丙烯(PP)为基础树脂,采用可控降解法生产了具有超高流动性的熔喷专用PP树脂RP1200,并通过了工业化应用试验。采用流变仪、凝胶渗透色谱仪、偏光显微镜及差示扫描量热仪对RP1200和进口同类树脂进行了对比研究。结果表明:RP1200与进口PP试样在相对分子质量及其分布、流变性能、微观结晶形态等方面较接近,但在结晶和熔融性能方面有较明显的差别;RP1200的结晶峰温度显著高于进口试样,且结晶峰较窄,即结晶速率更快;RP1200的熔融峰温度与进口试样较接近,但熔融峰较进口试样稍宽,说明其结晶完善程度的差异较大。在工业化应用中,RP1200的使用性能与进口PP树脂类似。     

扭结膜专用PP树脂及其薄膜的性能

在聚丙烯(PP)中加入扭结助剂制备了扭结膜专用聚丙烯(PP)树脂,并采用挤出流延的方法制备了流延聚丙烯薄膜,采用差示扫描量热法研究了PP的熔融和结晶行为,采用偏光显微镜观察了PP的结晶形态。加入的扭结助剂有阻碍PP结晶的作用,国产PP的结晶度下降了19.3%,但当PP结晶速率较快时,扭结助剂的效果可能会被抵消。加入扭结助剂后,用国产PP树脂制备的薄膜扭结性能和光学性能得到极大改善,且优于进口试样;薄膜的拉伸弹性模量和拉伸屈服应力与进口试样相近。     

聚丙烯结晶性能研究

通过差示扫描量热(DSC),X射线衍射(XRD),偏光显微镜(POM)等手段,研究了聚丙烯(PP)1102K,T30S及F401对比牌号试样的结晶性能。结果表明,3个牌号的PP中,1102K结晶温度和熔融温度最高,结晶速率较快,结晶效果较好,结构规整性较高。     

管材专用高密度聚乙烯的热分级研究

利用差示扫描量热法和连续自成核退火分级(SSA)法研究了PE100级管材专用高密度聚乙烯(HDPE)树脂的结晶熔融行为,三个牌号HDPE树脂的1-己烯共聚单体含量按试样1、试样2、试样3逐渐降低。结果表明:两种方法得到的结晶度和熔融温度均按试样1、试样2、试样3递增,且SSA处理后试样的结晶度和熔融温度较高;短链支化度按试样1、试样2、试样3逐渐降低;试样3表现出最佳的刚性和较低的韧性,而试样1则相反。     

薄膜专用PP树脂加工性能的凝胶渗透色谱评价

用凝胶渗透色谱测定了不同批号的薄膜专用聚丙烯(PP)树脂T38F的相对分子质量及其分布,评价了产品的相对分子质量及其分布对加工性能的影响.测定结果的重复性和再现性良好.根据分析结果调整相关工艺条件后生产的PP T38F能够满足用户的加工要求.实验结果表明:薄膜专用PP树脂的重均分子量(Mw)控制在(25.0～29.0)...     

刚性PP-B管材料的研制

选用不同的聚丙烯树脂、成核剂和抗氧剂进行熔融共混研究,制备出综合性能优良的刚性嵌段共聚聚丙烯管材专用料.对该专用料的力学和结晶性能的分析表明,它的物性指标达到了国外同类产品的技术水平.其中弯曲模量为1 550 MPa,氧化诱导期大于25 min,且加工性能优良.管材外观满足使用要求,并通过了1 000 h的静液压实验.     

煤基均聚聚丙烯1102K与同类产品热性能及流变性能对比

研究了煤基均聚聚丙烯1 102K和市场同类产品T30S,F401的熔融温度、结晶温度、氧化诱导期、热分解温度、毛细管流变性能及螺旋流动长度。结果表明:1102K的氧化诱导期为14.8 min,热分解温度为426℃,两项均高于T30S,F401,说明1102K的耐热性能最好;相同测试条件下,1102K的毛细管剪切黏度高于T30S和F401,而螺旋流动长度低于T30S和F401,说明1 102K的流变性能比T30S和F401稍差。     

CPP薄膜专用三元共聚聚丙烯的结构与性能

分析了流延聚丙烯薄膜专用二元无规共聚聚丙烯W0723F与3种三元无规共聚聚丙烯的基本热力学性能、凝聚态结构、相对分子质量及其分布、结晶性能及流变性能。结果表明:二元无规共聚聚丙烯弯曲模量高,熔点高;3种三元无规共聚聚丙烯中1-丁烯含量相差不大,摩尔分数为5.1%~5.4%,乙烯含量相差较为明显,摩尔分数为3.0%~9.0%;两种进口产品的分子链序列结构中包含乙烯共聚链段,熔点低、熔融峰宽、晶体粒径小,产品具有较低的起始热封温度;流变性能分析表明,国产产品的加工流动性较好。     

口罩聚丙烯熔喷纤维与聚丙烯熔喷原料的塑化及结晶行为对比研究

为阐明口罩过滤层聚丙烯(PP)熔喷纤维与熔喷PP塑料的塑化和结晶行为间的差异性,采用差示扫描量热仪(DSC)和热台偏光显微镜系统研究了3种熔喷PP塑料与4种口罩过滤层PP熔喷纤维的塑化和结晶行为.结果表明,PP熔喷塑料试样3显示单峰,PP熔喷纤维试样5呈现3峰,而其余PP熔喷塑料和PP熔喷纤维均呈现双峰;与PP熔喷塑料...     

Evaluation of the oxidative stability of multiextruded polypropylene as assessed by physicomechanical testing and simultaneous differential scanning calorimetry–chemiluminescence

Common physicomechanical tests comprising impact strength, the melt flow index (MFI), and the yellowness index (YI) were used to study the thermooxidative stability of polypropylene (PP) following multipass extrusion. Differential scanning calorimetry (DSC) coupled with chemiluminescence (CL) monitoring was also used to assess the stability. Three PP formulations were studied: (i) PP‐1 containing 0.050% w/w of the phenolic antioxidant Irganox 1010^™, (ii) PP‐2 containing 0.028% w/w Irganox 1010, 0.056% w/w of the phosphite costabilizer Irgafos 168^™ and 0.014% w/w of the lactone processing stabilizer HP 136^™, and (iii) PP‐3 containing 0.050% w/w Irganox 1010 and 0.100% w/w of the phosphite Ultranox 641^™. All formulations contained 0.045% w/w of the hydrotalcite acid scavenger DHT‐4A^™. The results suggest that physicomechanical tests cannot reliably detect the small difference in the stability between PP‐2 and PP‐3 but can detect the larger difference between these and the less stable PP‐1. The oxidative induction time (OIT) determined by CL monitoring (i.e., CL– OIT) is consistent with the OIT determined by DSC but has better reliability. The CL–OIT data suggest that PP‐3 has superior oxidative stability to PP‐2 in the early stages of multipass extrusion. However, PP‐2 exhibits a better resistance to yellowing. A correlation between the CL–OIT data and each of the MFI and YI data was found. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 733–741, 2001     

复合抗氧剂在煤基聚丙烯中的应用研究

分别采用不同质量比的1010和168复合抗氧剂、硬脂酸钙制备出一系列煤基PP S1003,通过不同温度下氧化诱导期(OIT)测试、多次挤出熔体流动速率测试、黄色指数YI测试等对S1003中的热氧稳定性、加工稳定性进行了分析研究.结果表明,随着主辅协同抗氧剂体系当中1010含量的提升,抗氧剂所稳定S1003体系相同温度下...     

基于三元复合抗氧剂体系煤基PP的使用寿命预测研究

设计了一系列基于受阻酚类抗氧剂(Irganox?1010、Irganox?1076)、亚磷酸酯类抗氧剂(Irgafos?168)和内酯型碳自由基捕捉剂(Revonox?501)的复配体系,应用于煤基聚丙烯(PP)抗热氧老化性能的改善.通过热台偏光显微镜、差示扫描量热仪(DSC)分析了不同抗氧剂复配体系对PP的影响规律;...     

Thermo‐oxidative degradation behavior of recycled polypropylene

This study has been carried out to mimic the thermo‐oxidative degradation of polypropylene (co‐PP) during service life and recycling. Injection molded specimens were heat aged at 130°C for different times up to maximum of 300 h to simulate the degradation of co‐PP during the service life. These aged specimens were mixed with stabilizers in internal mixer and again heat aged up to 300 h. A small increase in melt flow rate (MFR) value was observed for aged co‐PP but it showed large increase after recycling. The presence of carbonyl peak at 1713 cm⁻¹ confirmed the oxidation of co‐PP during aging and it increases with aging time. Carbonyl index (CI) is increased in recycled sample with aging, whereas oxidation induction time (OIT) decreased. The stabilizers used during reprocessing are quite effective in controlling the thermo‐oxidative degradation of the polymer during processing and aging. The thermogravimetric analysis shows that the onset of degradation temperature starts at low temperature for recycled sample as compared to virgin co‐PP. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Isothermal crystallization behavior and melting characteristics of injection sample of nucleated polypropylene

The isothermal crystallization behavior and melting characteristics of pure polypropylene (PP) and PPs nucleated with a phosphate nucleating agent (A) and a sorbitol derivative (D) have been studied by differential scanning calorimetry (DSC). Compared with pure PP, nucleated PPs show a shorter half‐times of crystallization. Dependence of crystallization rate of nucleated PP on the crystallization temperature is stronger than that of pure PP at the higher crystallization temperature, whereas the opposite results are obtained at the lower crystallization temperature. Addition of nucleating agent shifts the temperature at the deviation from the baseline of DSC melting curve, T, and the temperature at the completion of melting, T, to higher temperatures, indicating that nucleated PPs exhibit a higher perfection of PP crystals. A shoulder peak in the high temperature range of melting peak of nucleated PP and a wider low temperature region in the melting peak of pure PP are observed. Obviously, PP and nucleated PPs form different distribution of crystal perfection in the isothermal crystallization process. According to the half‐time of crystallization, nucleating agent A is more effective than D. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2547–2553, 2000     

The synergistic mechanism of thermally reduced graphene oxide and antioxidant in improving the thermo-oxidative stability of polypropylene

The feasibility of using thermally reduced graphene oxide (TrGO) to improve the antioxidative efficiency of commercial antioxidant (3,5-di-tert-butyl-4-hydroxycinnamic acid, AO) on unstabilized polypropylene (PP) was evaluated in terms of the oxidation induction time (OIT) and the initial degradation temperature (T_i). It was found that a synergistic effect exist between AO and TrGO in retarding the degradation of PP in oxygen-containing atmosphere. Compared with that of PP/AO (100/0.5) sample, the OIT value of PP/AO/TrGO (100/0.5/1) composite was almost doubled at 180 °C and the value of T_i in air was improved by 37.2 °C. As verified by using radical scavenging assay with the 1,1-diphenyl-2-picrylhydrazyl radical, the TrGO sheets exhibited a good radical scavenging capacity. The synergistic stabilization mechanism was attributed to the enhanced dispersion of TrGO sheets in the PP matrix in the presence of 0.5 wt.% AO, which could improve the oxygen barrier effect and radical scavenging efficiency of TrGO. This synergistic effect between AO and TrGO can efficiently reduce the concentrations of oxygen and peroxy radicals in the PP matrix, leading to the significant improvement in thermo-oxidative stability of PP/AO/TrG composite.     

超临界CO2辅助挤出制备PP/POE共混物微观形态与性能

采用带有超临界CO2注人装置的双阶挤出机组制备了聚丙烯/乙烯一辛烯共聚物(PP/POE)(100/10)共混物。采用扫描电子显微镜观察了PP/POE共混物脆断面的微观形态,利用ImagePro Plus软件定量分析了弹性体POE粒子在PP基体中分散的平均粒径和粒径分布,通过差示扫描量热仪和偏光显微镜考察了PP/POE共混物的结晶过程。结果表明,当超临界CO2注人量为2. 5份(样品PP2. 5)时,弹性体POE粒子在PP基体中的分散粒径最小,粒径分布最窄;其中最小平均粒径为0.34 μm,粒径分布为1. 44;样品PP2. 5的结晶度最高,为53. 57%,且具有最细小致密的晶体形态。     

新型三元复配抗氧体系的设计及其在煤基均聚PP中的应用

设计了一系列由主抗氧剂、辅助抗氧剂、碳自由基捕捉剂组成的不同种类、不同配比抗氧剂体系,并将其用于煤基均聚聚丙烯（PP）的抗热氧老化性能改性中。其中以巴斯夫抗氧剂 Irganox®1010、Irgafos®168主辅抗氧剂质量比1∶1为对比基准,通过测试并对比添加新型三元复配抗氧体系改性 PP的氧化诱导时间（OIT）、黄色指数、熔体流动速率、力学性能等性能指标,从而开发煤基均聚PP的最佳耐热氧老化助剂配方。结果表明,当主抗氧剂为Irganox®1010、辅抗氧剂为 Irgafos®168质量比为 1∶1并与羟胺类抗氧剂 Revonox®420复合使用时,改性 PP的 OIT最长为 9. 8 min,黄色指数为 1. 3,熔体流动速率为 10. 7 g/10 min,综合性能最佳;当主抗氧剂为 Irganox®1010、辅抗氧剂为 Irgafos®168质量比为1∶2时,改性PP的抗黄变效果最好,由此设计并优化的抗氧剂体系及其配比对煤基均聚PP的耐长期热氧老化 改性配方设计具有重要的启示。     

Crystallization and melting behaviour of polypropylene/barium sulfate composites

The effects of polypropylene (PP)–barium sulfate (BaSO₄) interfacial interaction on the crystallization and melting behaviour of PP/BaSO₄ composites were investigated by means of differential scanning calorimetry. The results show that BaSO₄ can act as nucleating agent and the nucleation activity increases when the PP–BaSO₄ interface is modified. Neat PP exhibits a single fusion endotherm after being non‐isothermally crystallized, whereas the PP/BaSO₄ composites show dual endotherms or a broad endotherm with a shoulder at the low temperature side, indicating that there are more crystallites with less perfection formed in the composite samples. It is shown that the hindrance of BaSO₄ particles on the transport of PP chains to the crystallization zone is responsible for the formation of the less perfect crystallites. Moreover, the melting patterns of the composites are different from sample to sample, which can be attributed to the different extents of deviation from equilibrium at which the crystallization processes proceeded. Copyright © 2004 Society of Chemical Industry