透明尼龙PA6T/6I在GF增强PA66体系中的应用

采用尼龙66 (PA66)和透明尼龙PA6T/6I为基体树脂,用熔融共混改性的技术方法制备PA66/PA6T/6I/GF复合材料,考察了透明尼龙PA6T/6I含量对复合材料的熔融结晶行为、热变形温度(HDT)、力学性能、表面性能的影响。结果表明,当玻璃纤维含量为30%的情况下,在透明尼龙树脂PA6T/6I用量不高于基体树脂含量的20%时,改性复合材料熔融结晶行为与PA66类似,复合材料制品表面的浮纤问题得到解决,比未添加透明尼龙PA6T/6I的复合材料相等的拉伸强度和弯曲强度分别提高27%和40%,简支梁和悬臂梁缺口冲击强度则分别提高了26%和40%,吸水率提高了30%,具有优异的综合性能和尺寸稳定性。     

尼龙6/硼酸镁晶须复合材料的制备与研究

使用自制的硼酸酯偶联剂BE-1和BE-2在硼酸镁晶须表面引发聚合形成有机涂层,用改性后的硼酸镁晶须制备尼龙6/硼酸镁晶须复合材料并对其性能进行了研究。结果表明:随着硼酸镁晶须含量的增加,复合材料的拉伸强度、弯曲强度及热变形温度出现了先增加后降低的趋势,当硼酸镁晶须在复合材料基体中的含量为30%时,复合材料的力学性能最佳,BE-1改性的尼龙6/硼酸镁晶须复合材料拉伸强度、弯曲强度、冲击强度、热变形温度分别比未改性的尼龙6/硼酸镁晶须复合材料提高了14.47%、13.72%、29.73%和7.19%;BE-2改性的尼龙6/硼酸镁晶须复合材料的拉伸强度、弯曲强度、冲击强度、热变形温度分别比未改性的尼龙6/硼酸镁晶须复合材料提高了23.37%、22.54%、37.84%和10.78%。     

尼龙6/PP-g-马来酸酐共混物及其熔纺初生纤维性能研究

用马来酸酐接枝聚丙烯共聚物(PP-g-MAH)对尼龙6进行共混改性,通过双螺杆挤出机共混制成切粒,接着将切粒烘干后进行熔融纺丝,研究共混改性尼龙6(MPA)及其初生纤维的力学性能。研究结果表明:熔体流动速率随着PP-g-MAH的增加而减小;而MPA初生纤维的最大可拉伸比和不同拉伸倍数下的拉伸丝模量都呈先增大后减小的趋势,都是在马来酸酐接枝聚丙烯含量为10%时达到最大值。     

原位熔融挤出制备高性能PA6的研究

以二苯甲烷双马来酰亚胺(BMI)为交联剂,采用原位熔融挤出交联反应法制备了高性能的尼龙6,研究了BMI用量对改性尼龙6力学性能、热性能和表观黏度的影响.结果表明:BMI和尼龙6发生了交联反应,使尼龙6的黏度增加.随BMI用馈增加,其拉伸强度、断裂伸长率、冲击强度和热变形温度都呈现出先增加后减小的趋势;拉伸强度和热变形温度在BMI用量达到1.0%时,达到最大值;而冲击强度和断裂伸长率在BMI用量为0.5%时,达到最大值.     

熔融条件对TPU/尼龙1010共混体系中尼龙1010熔融行为的影响

本文利用差示扫描量热仪DSC研究了熔融温度与熔融时间对聚酯型热塑性聚氨酯弹性体(TPU)/尼龙1010共混体系中尼龙1010熔融行为的影响。不同的熔融温度和熔融时间对TPU/尼龙1010的熔融行为的影响表明,在熔融温度为195℃时,尼龙1010的熔融峰为双峰;在熔融温度为210 oC和225 oC时,熔融峰为单峰;在熔融温度为230 oC时,尼龙1010的熔融双峰逐渐靠拢,TPU含量达到80%时,尼龙1010的熔融峰消失。随着熔融时间的延长,在TPU含量为20%时,尼龙1010的熔融双峰逐渐靠拢变为单峰,在TPU含量为40%和60%时,尼龙1010的熔融峰为单峰,熔融峰位置向低温方向移动,熔融峰温度大幅度降低;当TPU含量达到80%,尼龙1010的熔融峰消失。     

增塑剂对尼龙6性能与结晶行为的影响

研究了不同含量的苯磺酰胺增塑剂JZ-218对尼龙6力学性能、结晶行为以及热稳定性的影响.结果表明,随着增塑剂含量的增加,拉伸强度、弯曲强度与弯曲模量逐渐下降,而断裂伸长率、冲击强度与熔体质量流动速率逐渐提高.且增塑剂含量越高,改性尼龙6的熔融温度、结晶温度与玻璃化转变温度越低,但结晶度略有提高.此外,随着增塑剂含量的增...     

双恶唑啉对尼龙6改性作用的研究

以双恶唑啉为扩链剂,通过熔融挤出对尼龙6进行改性作用的研究.结果表明:双恶唑啉的用量存在最佳值,用量不足时偶联反应不充分,用量过多时封端反应加剧.扩链剂用量为最佳值时,扩链后尼龙6的特性黏度从0.96 dL/g增加到1.17 dL/g,端羧基含量和熔体指数分别降低为初始值的20%和38%.差式扫描量热分析表明:扩链后的尼龙6结晶度降低,扩链后尼龙6的缺口冲击强度有所提高.     

抗菌尼龙6纤维的制备及其性能的研究

用硅烷偶联剂处理过的载银纳米氧化锌抗菌剂与尼龙6切片共混制得抗菌尼龙6母料,通过熔融共混纺比投菌剂含量不同的抗菌尼龙6纤维,采用视频接触角测量仪,扫描电子显微镜、通用材料试验机、差示扫描量热仪等对抗菌剂表面改性效果及抗菌尼龙6纤维的结构形态,力学性能及结晶性能等进行了研究。结果表明：修饰后的抗菌剂表面呈疏水性,改善了与尼龙6基体的相容性,在尼龙6基体土均匀分散,与纯尼龙6纤维相比,抗菌尼龙6纤维的结晶温度和结晶速率有所提高,结晶度略有降低,抗菌尼龙6纤维的力学性能稍有下降,对大肠杆菌,金黄色葡萄球菌的杀菌率均达97％以上.     

尼龙6/碳纳米管浇铸成型的反应动力学

将改性的多壁羟基碳纳米管分散在熔融的己内酰胺中,一步原位聚合制备MC(单体浇铸)尼龙6/碳纳米管复合材料;采用非等温反应动力学分析方法对尼龙6/多壁碳纳米管浇铸成型的反应过程进行研究.结果表明:随着改性碳纳米管含量的增加,反应活化能及指前因子增加;MC尼龙6及其碳纳米管复合材料成型过程的反应级数都在0.9 ～1之间,可以认为是准一级反应.     

NMA与纳米SiO2复配对PA6热性能及力学性能的影响

N-苯基马来酰亚胺与马来酸酐的共聚物(NMA)对尼龙(PA)6具有良好的耐热改性作用,纳米Si O2能够较好地改善PA6的力学性能。采用自制的NMA与纳米Si O2以不同质量配比复配,对PA6进行共混改性,利用差示扫描量热法、热重分析、热变形温度和力学性能等表征方法研究了不同复配比例对PA6热性能及力学性能的影响。结果表明,随着纳米Si O2含量增加,PA6/NMA/纳米Si O2复合材料的熔融温度、结晶温度、结晶度及熔融焓均呈现先上升后下降的趋势;当NMA与纳米Si O2的质量比为10∶0时,复合材料的热稳定性最好;当NMA与纳米Si O2的质量比为8∶2时,复合材料的弯曲强度、弯曲弹性模量、拉伸强度和热变形温度均达到最大值,分别为108.3,2 989,77.6 MPa以及68.4℃,较纯PA6分别提高了19.0%,25.3%,11.7%和19.2%。随着纳米Si O2含量的增加,复合材料的熔体流动速率呈现先增加后减小的趋势。     

Drawing and ultimate tensile properties of nylon 6/nylon 6 clay composite fibers

This study systematically investigated the drawing and ultimate tenacity properties of the Nylon 6 (NY6)/nylon 6 clay (NYC) composite fiber specimens prepared at varying NYC contents and drawing temperatures. The achievable draw ratio (D_ra) values of NY6_x(NYC)_y as‐spun fiber specimens initially increase in conjunction with NYC content, and then approach a maximum value, as their NYC contents and drawing temperature approach the 0.5 wt% and 120°C, respectively. The percentage crystallinity (X_c) values of NY6_x(NYC)_y as‐spun fiber specimens increased significantly, as their NYC contents increased from 0 to 2 wt%. As revealed by high power wide angle X‐ray diffraction analysis, α form NY6 crystals grew at the expense of γ form NY6 crystals originally present in NY6_x(NYC)_y as‐spun fiber specimens as their draw ratios increased. The ultimate modulus, tenacity, and orientation factor values of NY6_x(NYC)_y fiber specimens approach a maximum value, as their NYC contents and drawing temperatures approach the 0.5 wt% and 120°C optimum values, respectively. The thermal and melt shear viscosity experiments were performed on NY6_x(NYC)_y resins and/or fiber specimens to determine the optimum NYC content and possible deformation mechanisms accounting for the interesting drawing, orientation, and ultimate tenacity properties found above. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

Mechanical properties of nylon 6 fibers gel-spun from benzyl alcohol solution

The drawing behavior and mechanical properties of gel-spun nylon 6 fibers were investigated in relation to the growth rate and morphology of gels. The sol-gel transition temperature of a nylon 6/benzyl alcohol solution increased with polymer concentration and, at higher concentration, appeared with gel melting. From the measurements of gelation time, the growth rate of gels was estimated assuming an Arrhenius type of gelation rate. It was found that gel growth of nylon 6 in benzyl alcohol was nearly three-dimensional, evidenced by the presence of spherical gels observed in the scanning electron microscope. A draw of asspun fibers was performed at one-stage or two-stage hot drawing. Modulus and tenacity increased with increase of the draw ratio and were nearly independent of the draw temperature. A two-stage draw was more effective to obtain a higher modulus than that of the one-stage draw and it was ascribed to the difference in the molecular orientation mechanism. However, it was difficult to obtain a higher modulus than 6.2 GPa by the gel-spinning of nylon 6 in this study and it was regarded as a result of the presence of spherical gels which hindered the sample to elongate to a higher draw ratio. © 1996 John Wiley & Sons, Inc.     

Polar and Non-Polar Solvent Permeation Resistance of Blow-Molded Bottles of Polyethylene/Blends of Modified Polyamide and Polyamide 6 Clay Nanocomposite

Investigations on white spirit and acetone permeation resistance of modified polyamide and nylon 6 clay (MPANYC) blends and their corresponding polyethylene/MPANYC bottles were reported in this study. The white spirit and acetone permeation resistance of MPANYC sheets improve consistently with increasing NYC contents present in MPANYC resins after blending nylon 6 clay (NYC) in modified polyamide (MPA) resins. However, the order of barrier improvement of the PE/MPANYC and PE/NYC bottle specimens is not corresponding to the order of barrier improvement of the MPANYC and/or NYC barrier resins added in PE. The blow-molded PE/NYC bottle specimen exhibits similarly worse white spirit and acetone solvent permeation resistance as the PE bottle specimen, wherein no clearly formed NYC laminas but only dispersed NYC droplets or agglomerates were found on the fracture surfaces of the PE/NYC bottles. However, after blending optimum compositions of MPANYC in PE, the PE/MPANYC bottles with demarcated MPANYC laminas exhibit significantly better white spirit and acetone permeation resistance than the PE/MPA bottle, wherein the white spirit and acetone permeation rates of the PE/MPA₈NYC₁ bottle are about 1.3 and 1.4 times slower than those of the PE/MPA bottle, respectively. In order to understand these interesting barrier properties of PE/MPANYC and PE/NYC bottles, rheological, thermal, wide angle X-ray diffraction and morphological properties of the base MPANYC and NYC resins and their corresponding morphology present in the blow-molded bottles were investigated.     

Dynamic viscoelastic behavior of styrene-grafted nylon 6 fiber

Styrene-grafted nylon 6 fibers which had been prepared by the UV irradiation method were investigated by dynamic viscoelasticity and dilatometry. It was found that nylon 6 is relaxed and polystyrene is simultaneously plasticized by nylon 6 during grafting. These phenomena are interpreted as follows. The grafting process causes nylon 6 to have a lower glass transition temperature and increases grafting frequency of polystyrene to nylon 6 by increasing the chemical junctions between the two components, so that they necessarily become more compatible.     

Effect of moisture absorption on the dynamic mechanical properties of short carbon fiber reinforced nylon 6, 6

A study of hygrothermal aging in terms of the kinetics of moisture absorption by nylon 6,6 and its carbon fiber reinforced composites has been carried out. The single free phase model of absorption has been applied to the kinetic data and thereafter the values of diffusivity have been evaluted. The diffusivity was found to be dependent on the conditioning temperatures and the volume fraction of fibers. Dynamic mechanical properties of unaged and aged samples were studied using a free resonance torsion pendulum which covers a temperature range of 350°C. Incorporation of carbon fibers has led to an increase in structural rigidity of the nylon 6,6 matrix especially at higher temperatures. This was reflected by the sharp increase in the relative shear modulus as the glass transition temperature of nylon 6,6 is appoached. Absorbed moisture was observed to plasticize the polymer matrix and decreased the temperatures of all the transitions. For instance, the α-transition was shifted by almost 95°C. The intensities of the transition peaks of both unaged and aged samples were found to decrease with fiber volume fraction. Increasing the conditioning temperatures has resulted in a reduction of the shear storage modulus and this effect was found to be more pronounced in the reinforced nylon 6,6. This has been attributed to the increase in the extent of degradation at the fiber-matrix interface.     

A new synthetic fiber made of nylon 3

Nylon 3 fibers were produced by wet spinning, and properties and structures of the fibers were investigated. Fiber- and film-forming abilities of nylon 3 dopes in various coagulants, using various solvents, were investigated and it was found that only the nylon 3 spinning dope dissolved in formic acid showed excellent fiber- and film-forming abilities in coagulation baths of ethers, esters, or alcohols. As for mass transportation in these coagulants, solvent (formic acid) was diffused into coagulants, with scarce penetration of the coagulants into protofibers. This was due to the fact that these coagulants had moderate solubility parameter values and moderate proton-accepting power, which means the existence of some interaction between solvent and coagulants and no interaction between coagulants and polymer. Protofibers thus obtained were already crystallized and stretching them at room temperature was impossible. However, in such media as silicone oil, hot air, and Wood's metal, which were thought to have no interaction with polyamides, nylon 3 fibers were stretchable above their glass transition temperature (170°–180°C), while in such media as hot water, hot glycerin, and hot steam, which were thought to have some interaction with polyamides, nylon 3 fibers could not be stretched. Mechanical properties of nylon 3 fibers were as follow: strength, 2–3 g/d; elongation, 10%–20%; Young's modulus, 11 × 10⁵–17 × 10⁵ psi. High Young's modulus, high transition temperature, and high moisture regain are pointed out as characteristic features of nylon 3 fibers, compared with other synthetic fibers.     

Transcrystalline morphology of nylon 6 on the surface of aramid fibers

In this paper, the isothermal crystallization of nylon 6 in the presence of Kevlar 129 fiber was investigated by polarized optical microscopy (POM). The formation of a transcrystalline domain was found to be mainly controlled by crystallization conditions, such as the temperature of the isothermal crystallization, residual time at melting temperature and the cooling rate of the melt. The nucleation rate of nylon 6 on the fibers was mainly affected by the crystallization temperature. The interfacial transcrystallinity of nylon 6 occurred on the surface of Kevlar 129 fiber in the temperature range 130–190 °C. The reason for the formation of interfacial transcrystalline morphology is discussed from the molecular level, based on the understanding of the packing mode of nylon 6 chains around fibers and the interaction between matrix and fibers. It was found that the lattice matching and hydrogen‐bonding between nylon 6 and poly(p‐phenylene terephthalamide) (PPTA) crystals play an important role in the epitaxial crystallization. Copyright © 2004 Society of Chemical Industry     

The effects of a nucleating agent and of fibers on the crystallization of nylon 66 matrices

Crystallization from the melt of nylon 66 in the presence of carbon fiber, aramid fiber, or nucleating agent was studied using differential scanning calorimetry (DSC) and hot stage microscopy. The use of the nucleating agent resulted in an increase in crystallization rate and a decrease of induction time under both isothermal and nonisothermal conditions. The fibers were found to behave like a giant nucleating site producing a uniform transcrystalline layer having morphology and crystallization kinetics different from those of the bulk matrix. The influence of the cooling rate on the process of nonisothermal crystallization was analyzed, and the values of activation energy, calculated from the cooling rate—crystallization temperature relationship, appeared to be higher for the nucleated and for the reinforced nylon compared with that of the neat nylon 66. This implied that the presence of fibers or nucleating agent led to the development of a more ordered structure, which required a larger amount of energy for crystallization.     

Interpretive nonlinear viscoelasticity: Dynamic properties of nylon 6, nylon 66, and nylon 12 fibers

Nonlinear response of nylon 6, nylon 66, and nylon 12 fibers to sinusoidal straining under relatively large strain amplitude is analyzed in terms of the changes in properties during the straining, i.e., the change in modulus, change in internal friction and change in structure which involves energy release or absorption in straining. Modulus generally increases with strain but it decreases with increase of strain amplitude, the effect of strain amplitude being largest with nylon 6 and smallest with nylon 66. Mechanical loss increase with the increase of strain amplitudes in nonlinear manner, and the magnitude of change is largest with nylon 66 and smallest with nylon 6. During the extension phase, structural change occurring in nylon 6 is predominantly an increase in order or orientation while that with nylon 66 is crack opening or cavitation. Various aspects of the experiments and analysis of the data are described in detail.     

纳米尼龙/聚苯乙烯/马来酸酐复合材料性能的研究

通过马来酸酐(MAH)对聚苯乙烯(PS)接枝改性制得聚苯乙烯接枝马来酸酐共聚物(PS-g-MAH),然后将PS-g-MAH与纳米尼龙(NYC)按不同比例共混,制得纳米尼龙/聚苯乙烯接枝马来酸酐复合材料(NYC/PS-g-MAH),对其结构、力学性能及阻燃性能进行了表征分析。结果表明:NYC/PS-g-MAH复合材料的力学强度和阻燃性能有所提升,其抗冲击强度最大可达到6.0×102kJ/m2,拉强度最大可达到72.5 MPa,氧指数可以达到23%。