PP/PA6/离聚物共混物的结构及力学性能

以乙烯-甲基丙烯酸钠盐离聚物(Surlyn8920)为添加剂,采用双螺杆共混和注塑法制备了聚丙烯(PP)/聚酰胺6(PA6)/Surlyn共混物,然后利用红外光谱测试仪、X射线衍射仪、差示扫描量热仪、扫描电子显微镜等对PP/PA6/Surlyn共混物的结构和力学性能进行了表征分析。结果表明,Surlyn与PA6发生络合作用,降低了PP与PA6两相的结晶温度、熔融温度、结晶度和结晶完善程度,使得分散相PA6的尺寸更小,分布更加均匀,明显改善了PP和PA6的界面相容性;当Surlyn的含量为7%(质量分数,下同)时增容效果较好,此时共混物的拉伸强度为40.59 MPa,断裂伸长率为156.3%,冲击强度为4.98 kJ/m~2。     

PP-g-MAH对PA6/PP共混体系性能的影响

以PP-g-MAH为相容剂,研究了PP-g-MAH对PA6/PP共混体系性能的影响。探讨了PP-g-MAH对PA6/PP共混物增容作用,提高共混物的各项性能指标。当PP-g-MAH为4份时,共混物的力学性能最好,当PA6/PP=90/10时,其力学性能有最大值;SEM照片显示,未加PP-g-MAH时,PP在PA6基体上分散不均,颗粒大,当加入适量的PP-g-MAH(4份)时,PP分散比较均匀,颗粒尺寸明显降低。以PP-g-MAH4份,PA6/PP=80/20制备的共混物,吸水率约是PA6的15%:冲击强度、热变形温度分别比PA6、PP提高了72%和106%,13.5℃和5.5℃。     

纳米蒙脱土对PA66/PP共混物结构与性能的影响!

通过融挤出制备了PA66/PP/纳米蒙脱土(OMMT)共混物,采用广角X射线衍射(WAXD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等研究了OMMT在PA66/PP共混物中的分散及其对PA66/PP共混物力学性能、结构的影响。结果表明,OMMT主要为剥离状态分布于PA66/PP中。随OMMT含量增加,PP分散相尺寸逐渐减小,且5 phr OMMT时,PP分散相尺寸达到最小。PA66/PP/OMMT共混物的拉伸强度和模量呈上升趋势,缺口冲击强度下降。     

PA6/ABS共混及增容改性

以聚己内酰胺(PA6)为主体材料,将丙烯腈–丁二烯–苯乙烯塑料(ABS)与PA6共混,并加入马来酸酐接枝ABS (ABS-g-MAH)作相容剂,研究了ABS及相容剂ABS-g-MAH用量对PA6/ABS共混物力学性能的影响。结果表明,随着ABS用量增加,PA6/ABS共混物的拉伸强度下降,冲击强度先上升后下降,收缩率变化不大,ABS用量为10份时PA6/ABS共混物的综合性能较好。相容剂ABS-g-MAH对PA6/ABS共混物的力学性能有较明显的影响,随着相容剂用量增加,拉伸强度和冲击强度均先上升后下降,相容剂用量3～9份时有利于共混物保持较高的拉伸强度和冲击强度。     

增容剂对PP/PA66共混物力学性能和结晶行为的影响

采用熔融共混法制备了聚丙烯(PP)/聚酰胺66(PA66)共混物,研究了聚丙烯接枝马来酸酐(PP-g-MAH)和乙烯-辛烯共聚物接枝马来酸酐(POE-g-MAH)作为增容剂对PP/PA66共混物力学性能和非等温结晶行为的影响。结果表明:PP-g-MAH提高了共混体系的拉伸强度,加入5份POE-g-MAH能显著提高共混物的断裂伸长率;PA66可起到异相成核作用,使PP的结晶峰温度升高;加入PP-g-MAH进一步提高了PP的结晶峰温度;PA66使PP的结晶活化能增大,增容剂的加入则使共混体系中PP的结晶活化能降低。     

新型PP/PA6的制备及其力学性能研究

通过反应增容结合互穿网络制备PP/PA6共混物,利用方差分析法分析了聚丙烯含量、溶胀温度、马来酸酐含量、溶胀时间对PP/PA6共混物力学性能的影响。结果表明,当聚丙烯含量在50%、溶胀温度为80℃、溶胀时间为135min时,PP/PA6的综合力学性能最好,共混物的拉伸强度达到20 989MPa,其冲击强度达到20 268kJ/m2。并通过扫描电镜对纯聚丙烯、纯尼龙6和聚丙烯/尼龙6共混物的形态结构进行了观察。     

POE-g-GMA对PP/PA6共混物力学性能的影响

采用熔融法制备乙烯-辛烯共聚物接枝甲基丙烯酸缩水甘油酯(POE-g-GMA)。利用红外光谱法和化学滴定法对接枝物进行结构表征及接枝率的测定。并将POE-g-GMA作为相容剂对PP/PA6共混物的力学性能的影响进行研究。研究结果表明:在PP/PA6共混物中加入适量的PA6可以提高PP的拉伸强度,当在PP/PA6共混体系中加入相容剂POE-g-GMA,不仅能够改善PP/PA6共混物的相容性,而且能够使PP/PA6共混物在保持较高拉伸强度和弹性模量的同时,大幅度地提高共混物的缺口冲击度和断裂伸长率,与纯PP相比提高幅度显著增大。     

PP-g-GMA的制备及其增容PP/PA6共混物的性能

通过熔融接枝反应制备了甲基丙烯酸缩水甘油酯接枝聚丙烯（PP-g-GMA）,并将其作为聚丙烯/聚酰胺6（PP/PA6）共混物的相容剂,研究了PP-g-GMA对PP/PA6共混物的力学性能及形态结构的影响。结果表明,采用滴定法测得PP-g-GMA接枝率为3.35 %;当PP-g-GMA的添加量为4 %（质量分数,下同）和8 %时,PP/PA6/PP-g-GMA共混物的拉伸强度和缺口冲击强度分别较PP/PA6共混物提高了32.4 %和60.4 %;PP-g-GMA显著改善了PP/PA6 共混物的界面相容性,是PP/PA6共混物的有效增容剂。     

POE-g-MAH对PP/PA6共混体系形态结构与力学性能的影响

研究了乙烯-辛烯共聚物接枝马来酸酐(POE-g-MAH)作为相容剂对PP/PA6共混体系相容性、形态结构和宏观力学性能的影响.研究结果表明在PP/PA6共混体系中加入相容剂POE-g-MAH,不仅能够显著改善PP/PA6共混物的相容性,明显降低分散相的粒径,而且能够使PP/PA6共混物在保持较高的拉伸强度和弹性模量的同时,大幅度地提高共混物的缺口冲击强度和断裂伸长率,与纯PP相比提高幅度分别达到198.3%和778.8%.POE-g-MAH增容PP/PA6共混体系的非等温结晶行为的研究表明,PA6作为成核剂使PP的结晶温度提高,POE-g-MAH的加入能进一步促进PA6对PP基体的异相成核作用.     

PA 6/碳纳米管共混导电单丝的制备和性能研究

将炭黑导电母粒、碳纳米管母粒、聚己内酰胺(PA 6)切片按一定质量配比共混,在双螺杆机挤压下,经注带、冷却制得共混切片,将共混切片在卧式纺丝机上进行纺丝,经拉伸、上油等制得导电单丝,研究了不同配比的导电单丝的导电性能和力学性能。结果表明:随着共混切片中炭黑和碳纳米管总量的减少、PA 6含量的增加,其纺丝时最大可拉伸倍数呈现单调上升;炭黑与碳纳米管在导电单丝拉伸过程中具有协同作用,拉伸后的导电单丝的表面电阻可达到10~4Ω/cm水平;炭黑母粒质量分数为40%,碳纳米管母粒质量分数为30%,PA 6质量分数为30%时,制得的导电单丝导电性能和力学性能好,其表面电阻为1.5×10~4Ω/cm,电阻率为4.2×10~5Ω·cm,断裂强度为12.2 cN/tex,断裂伸长率为12.3%。     

Polypropylene/polyamide 6/polypropylene-g-maleic anhydride blending monofilaments: effects of quench temperature

We describe the effects of quench temperature on the structure and mechanical properties of polypropylene/polyamide 6/polypropylene grafted maleic anhydride (PP/PA6/PP-g-PAH) blend monofilaments. The monofilaments were prepared by melt-spinning under different quench temperatures. The thermal properties were investigated by Differential scanning calorimetry (DSC) and the morphologies were observed using Scanning electron microscope (SEM). We measured the tensile strength, the loop strength, and the elongation at break of the monofilaments. Results demonstrated that the quench temperature had strong effects on the structure and mechanical properties of the PP/PA6/PP-g-MAH blend monofilaments. With the decrease of quench temperature, the tensile strength and the loop strength of the blend monofilaments increased obviously, which could be attributed to the different crystallization processes and orientation structures induced by changing quench temperatures.     

Nanoclay/Polypropylene Composite Monofilament Processing and Properties Using Twin and Single Screw Extruders

The structure and properties of nanoclay/polypropylene composite monofilaments were characterized using scanning electron microscopy, thermal gravimetric analyzer, differential scanning calorimeter, and Instron universal testing machine. Twin and single screw extruders were used to produce composite monofilaments with different weight percentage and types of nanoclays and compatabilizers. Final properties of composite monofilaments were affected by the amount of nanoclay. The tensile strength values decreased compared to the pure polypropylene monofilaments for all composite samples. There was not a significant change at melting point; however, decomposition temperature of composite polypropylene monofilaments increased about 10–18% compared to pure polypropylene monofilaments.     

Technological developments in making polypropylene surgical monofilaments

Special technology has been developed for the production of polypropylene surgical monofilaments to meet medical needs for a suture material meeting tight specifications for physical and mechanical properties. To produce polypropylene monofilaments having improved elastic properties and strength, studies have been made on the effects of technological parameters (temperatures of liquid and of cooling bath, molding rate, thermal drawing ratios and temperatures, the thermal stabilization temperature, and temperature of additional thermal treatment of existing monofilaments with or without shrinkage) as regards the strength, elongation, the strength and elongation in knots, and bending rigidity. Conditions are given for making surgical monofilaments of various diameters with improved manipulation and strength. Translated from Khimicheskie Volokna, No. 4, pp. 28–34, July–August, 2008.     

深冷处理对共聚酰胺单丝性能的影响

对共聚酰胺单丝实施深冷处理,通过对深冷温度、深冷时间、深冷次数进行三因素三水平正交试验安排,考察其对拉伸强度、耐磨性及结晶度三个指标的影响。结果表明:三因素对三个指标均有影响,主次顺序为深冷温度、深冷时间、深冷次数;经过正交试验的极差分析显示,当深冷温度为-190℃、深冷时间为10 h、深冷次数为2次时,共聚酰胺单丝的各指标性能较佳,为最佳试验方案。     

PP/PA6复合材料力学性能的研究

研究了PA6用量对PP、PP／SiO2拉伸强度的影响以及不同相容剂PP-g-MAH、POE-g—MAH对PP／PA6共混体系力学性能、相容性和结构的影响。通过力学性能测试、DSC热分析和SEM观察,研究了复合材料的性能。研究结果表明：PA6的加入可以提高PP、PP／SiO2体系的拉伸强度;两种相容剂的加入都可使PP／PA6体系的相容性增加,但PP-g—MAH的加入主要表现为增强效果,而PP—MAH的加入主要表现为增韧效果。     

High-Temperature Tensile Strength of Er2O3-Doped ZrO2 Single Crystals

The deformation and fracture mechanisms in tension were studied in single-crystal Er₂O₃-doped ZrO₂ monofilaments processed by the laser-heated floating zone method. Tensile tests were carried out between 25° and 1400°C at different loading rates and the dominant deformation and fracture mechanisms were determined from the shape of the stress–strain curves, the morphology of the fracture surfaces, and the evidence provided by monofilaments deformed at high temperature and broken at ambient temperature. The tensile strength presented a minimum at 600°–800°C and it was controlled by the slow growth of a crack from the surface. This mechanism was also dominant in some monofilaments tested at 1000°C and above, while others showed extensive plastic deformation before fracture at these temperatures. The strength of plastically deformed monofilaments was significantly higher than those which failed by slow crack growth due to the marked strain hardening capacity of this material.     

相容剂对PE-HD/回收纸塑铝复合材料性能的影响

分别以马来酸酐接枝聚乙烯(PE-g-MAH)、马来酸酐接枝乙烯辛烯共聚物(POE-g-MAH)、甲基丙烯酸甘油酯接枝乙烯辛烯共聚物(POE-g-GMA)为相容剂,采用熔融共混法制备了高密度聚乙烯(PE-HD)/回收纸塑铝包装粉末(r-PPA)复合材料。通过力学性能、流变性能、吸水率和扫描电子显微镜等分析,对3种相容剂的增容作用进行研究。结果表明,POE-g-GMA对复合材料力学性能影响最大,当添加量为6份时,复合材料的拉伸强度比未增容体系提高了32.9 %,脆断面出现韧性断裂的“拔丝”现象,且体系出现“类液类固”转变;PE-g-MAH对复合材料的吸水率影响最大,当添加量为10份时,复合材料的吸水率比未增容体系降低了54.2 %。     

环氧树脂对PA6/EPDM-g-MAH共混体系性能的影响

将两种不同型号的环氧树脂（EP(903)、EP(619D)）分别与PA6/EPDM-MA体系进行共混,制备了PA6/EPDM-MA/EP三元共混物。通过力学测试、动态流变(DMA)、差示扫描量热法（DSC）研究了不同EP添加量和环氧当量对PA6/EPDM-MA/EP共混体系性能的影响。实验结果表明：添加EP可以提高PA6/EPDM-MA共混物的拉伸强度,缺口冲击强度,并随着EP含量的增加而增加;而PA6/EPDM-MA/EP三元共混体系的动态储能模量（G′）,复合黏度（η*）随着EP含量的增加而增大,损耗因子（tanδ）减小;结晶度比未加环氧的共混物的结晶度稍高,并且随着环氧含量增加先增加后降低。此外,添加EP(903)的共混物各种性能变化比EP(619D)快。     

CPVC/PVC/ACR三元共混材料的研究

研究了CPVC／PVC/ACR三元共混材料的物理力学性能。结果表明，共混材料的维卡软化温度和拉伸屈服强度随CPVC用量的增加而增加；当ACR用量为6-8份时，可明显改善共混材料的抗冲性能。     

Microstructural Stability and Mechanical Properties of Directionally Solidified Alumina/YAG Eutectic Monofilaments

Fiber strength retention and creep currently limit the use of polycrystalline oxide fibers in ceramic matrix composites making it necessary to develop single crystal fibers. Two-phase alumina/YAG single crystal structures in the form of monofilaments show that the room temperature tensile strength increases according to the inverse square root of the microstructure size. Therefore, microstructure stability will play a significant role in determining the ‘use temperature’ of these fibers along with its creep resistance. In this work, the effects of temperature on microstructural stability and the creep behavior of directionally solidified alumina/YAG eutectic monofilaments were studied. Microstructural stability experiments were conducted in air from 1200 to 1500°C and creep tests at temperatures of 1400 to 1700°C. Inherent microstructure stability was found to be very good, however, extraneous impurity-induced heterogeneous coarsening was significant above 1400°C. The creep strength of monofilaments with aligned microstructures were superior to ones with low aspect ratio morphologies. Mechanisms for microstructural coarsening and creep behavior are discussed.