PETG/PC/TPU合金共混改性研究

采用双螺杆挤出机对聚氨酯(TPU)、聚碳酸酯(PC)和聚对苯二甲酸乙二醇酯-1,4-环己烷二甲醇酯(PETG)进行熔融共混,制备出PETG/PC/TPU三元共混物,研究了不同共混物的力学性能、耐溶剂性能、软化温度及微观形态结构等性能。研究发现,对于同样硬度的TPU,聚酯型TPU对改善合金的拉伸强度和冲击强度均优于聚醚型TPU与PETG/PC的共混。硬度较低的聚酯型TPU可较大幅度提高PETG/PC/TPU合金的韧性。TPU的加入可明显改善PETG/PC/TPU合金的耐溶剂性。     

FDM用PETG系列耗材的改性研究

对市售聚对苯二甲酸乙二醇酯-1,4-环己烷二甲醇酯（PETG）丝材及原材料进行研究,选用PETG 2012作为制备熔融堆积成型技术（FDM）用PETG丝材的基体树脂。选用聚碳酸酯（PC）对基体PETG进行增韧增强改性,并制成3D打印高分子丝材进行打印测试,探讨了PC含量对PETG耗材及制件性能的影响。结果表明,在低PC含量下,PETG与PC的相容性较好,PETG与PC制件未出现明显的分层,分布比较均匀;共混物的流动性随着PC含量的增加而降低,且打印件的维卡软化温度和热变形温度随着PC用量的增加而增加;此外,PC材料的加入使得PETG打印件的力学性能得到较大改善：打印件的拉伸强度随着PC用量的增加而增大,缺口冲击强度却随着PC用量的增加呈现先增加后减小的趋势; PETG/PC的配比为1∶1时,可制得力学性能优异的3D打印耗材。     

PETG/PC/TPU共混物的制备及结构性能

采用微型双螺杆挤出机,将聚对苯二甲酸乙二醇-1,4-环己烷二甲醇酯(PETG)、聚碳酸酯(PC)、聚氨酯(TPU)挤出共混,制备了PETG/PC、PETG/PC/TPU两种共混物,研究了两种共混物的透明性能、力学性能、相容性及微观结构等。结果表明:PETG/PC共混物具有良好透明性能和相容性,共混物断裂方式为韧性断裂;PC的加入提高了PETG/PC共混物的拉伸强度,但断裂伸长率有所降低;TPU的加入不影响PETG/PC体系的透明性,并能够提高体系的断裂伸长率。     

玄武岩纤维增强PVDF/PP/PETG共混物及性能的研究

通过熔融共混法制备了聚偏氟乙烯/聚丙烯/聚对苯二甲酸乙二醇1,4环己二醇酯（PVDF/PP/PETG）共混物,利用玄武岩纤维对其进行增强改性,并采用扫描电子显微镜、转矩流变仪、维卡软化点测试仪等测试仪器对共混物的形态、黏度、耐热性和力学性能等进行了研究。结果表明,230 ℃时,共混物中PVDF、PP和PETG属两两不相容体系,PVDF和PP呈现连续相结构,而PETG则以球状形态分散在体系中;经玄武岩纤维增强改性后,复合材料的拉伸强度和弯曲强度随着玄武岩纤维含量的增加而增大,且当其含量为30 %（质量分数,下同）时,复合材料的拉伸强度和弯曲强度分别增加到44.0 MPa和67.9 MPa;共混物的维卡软化点从126.7 ℃提高到141.7 ℃。     

PETG连续挤出发泡行为

采用环氧型扩链剂对苯二甲酸-乙二醇-1,4-环己烷二甲醇共聚酯(PETG)进行熔融扩链,并利用高级扩展流变仪、熔体强度测定仪和扫描电子显微镜分别进行了剪切流变、拉伸流变测试和连续挤出发泡行为研究。结果表明:扩链后PETG的储能模量、损耗模量、复数黏度随扩链剂含量的增加而增大,而其损耗因子随扩链剂含量的增加而减小;扩链剂的加入能有效提高PETG树脂的熔体强度和改善其"可发泡性",在发泡成型过程中可以有效阻止泡孔的塌陷和破裂,进而形成泡孔尺寸和形态分布较为均匀的制品。     

PETG特种片材用作身份证基材

日前由江苏华信塑业发展有限公司研发生产的PETG特种片材,被公安部定为全国第二代居民身份证卡片基材的专用材料。该PETG片材具有封装性能好、尺寸稳定性好、拉伸强度高、信息储存量大、不易磨损、使用寿命长、易于印刷、无污染等特点。该材料的各项性能指标全部达到制作第二代居民身份证卡片基材的要求,达到国际先进水平。     

基于正交试验的PETG/ABS复合制件熔融沉积成型工艺参数的优化

为了缩短熔融沉积成型(FDM)工艺的成型时间并改善产品的力学性能,采用FDM工艺方法对聚对苯二甲酸乙二醇-1,4-环己二甲醇酯(PETG)和丙烯腈-丁二烯-苯乙烯(ABS)两种线材进行3D打印,以成型时间、拉伸强度和拉伸弹性模量为优化指标,设计了基于正交试验法的三因素(打印速度、分层厚度、填充率)四水平的工艺参数优化方案。结果表明:PETG/ABS复合制件最优力学性能的参数组合是A4B1C3,即打印速度为30 mm/s、分层厚度为0.1 mm、填充率为75%。验证试验表明,拉伸强度为44.73 MPa、弹性模量为758.12 MPa、成型时间为113 min,优化参数后明显改善了力学性能,对双材料打印制品的生产具有一定的指导意义。     

PETG熔体流变性能的研究

对PETG共聚酯熔体的流变性能进行研究,讨论了树脂的粘度、加工温度以及加工助剂的影响,比较了PETG与PET流变性能的不同。结果表明,PETG的熔体强度可以进行调节。     

扩链剂联用对PETG扩链反应与流变性能的影响

通过扩链反应对聚对苯二甲酸乙二醇1,4环己烷二甲醇酯（PETG）进行改性以提高PETG的熔体强度和黏度。采用熔体流动速率仪、旋转流变仪及转矩流变仪考查了扩链剂的使用方式对PETG结构及流变性能的影响。结果表明,酸酐类和环氧类多官能团单体联用对PETG的扩链效果最好,PETG的熔体流动速率由12.83 g/10 min降低至7.50 g/10 min,零剪切黏度（η0）由2022.8 Pa·s增加到4764.2 Pa·s,特征松弛时间（τ0）由0.78 s增加到3.58 s;改性后PETG仍保持着线形结构而未形成凝胶。     

热收缩标签材料的发展现状

目前被广泛使用的热收缩标签有聚氯乙烯(PVC)、聚对苯二甲酸乙二醇酯-1,4-环己烷二甲醇酯(PETG)、拉伸聚苯乙烯(OPS)三种。本文介绍了PVC、PETG、OPS三种材料的特性以及其优缺点,并概述了这三种材料目前的发展现状。     

玻璃纤维建筑膜材的评价方法研究

简要介绍了膜结构建筑用膜材;介绍了玻璃纤维织物结构对膜材性能的影响;通过分析研究国外玻璃纤维膜材产品、国外膜材评价方法及标准,提出了玻璃纤维膜材的力学性能（拉伸断裂强力、断裂伸长率、折叠后拉伸断裂强力、撕裂强力、弹性常数）、耐候性（加速老化、耐雨水）、透光性、防火性评价方法。希望通过本文为玻纤膜材的评价和选择提供一定的帮助。     

水性聚氨酯／丙烯酸酯复合细乳液的研究

用细乳液聚合的方法制备水性聚氨酯／丙烯酸酯复合细乳液,研究了引发剂的种类与用量对乳液的影响,并对胶膜进行热重分析,同时根据实验标准测试胶膜的拉伸强度和剥离强度。实验表明：PU加入量为15％时,胶膜拉伸强度提高23％,此处的断裂伸长率和剥离强度也达到了最大值。     

高拉伸强度高延伸率丁羟弹性体的研究

综述了高拉伸强度高延伸率丁羟弹性体的几种改性方法。用自制的二聚脂肪酸二异氰酸酯（DDI）为固化剂制备的丁羟弹性体胶片具有优异的力学性能,最大拉伸强度达9.02 MPa,该强度下的延伸率达1 000%。指出以DDI为高性能固化剂的＂DDI固化体系＂是制备高拉伸强度高延伸率丁羟弹性体最为有效的途径,使用具有不同官能度的液体端羟基聚丁二烯进行复配的＂丁羟双模体系＂将是高强度高延伸率丁羟推进剂的主要研究方向。     

An investigation of the interfacial adhesion between reclaimed newspaper and recycled polypropylene composites through the investigation of their mechanical properties

The effects of different parameters (e.g. method of defibration of newspaper; size of the fiber; type and concentrations of coupling agents, impact modifiers, and fire retardants) on the mechanical properties of old newspaper fiber-filled recycled polypropylene (PP) have been evaluated. Statistical methods were applied to determine the effects of variables on the tensile strength, Young's modulus, tensile toughness, and impact strength. Statistical analysis revealed that the composites based on newspaper fiber prepared by mechanical defibration showed a better tensile strength compared with those prepared by the steam explosion process, while the latter type of fiber outperformed the former as far as the other mechanical properties are concerned. In the presence of maleic anhydride grafted PP (MPP) and the initiator dicumyl peroxide (DCPO), the tensile strength of the composites increased with increasing fiber loading and fiber size. Moreover, both the tensile strength and the modulus increased with an increase in the concentrations of MPP and DCPO, even in the presence of an impact modifier and fire retardants for surface-modified newspaper-filled composites. Since the tensile strength of short fiber reinforced composites is strongly dependent of the degree of adhesion between the fiber and matrix, the experimental results suggest that either one of these (MPP and DCPO) or both act as the interfacial bonding agent to develop a strong interphase between old newspaper fiber and recycled PP.     

碳纤维拉伸性能测试方法精密度研究

通过对国内有代表性的13家碳纤维企业和专业实验室的循环比对试验结果进行统计分析和研究,首次得到了碳纤维拉伸性能试验法可重复性和再现性的精密度数据,为准确测定和评价碳纤维的拉伸强度和模量提供了科学依据。     

含乙酸木素复合型聚氨酯材料的合成及其性能研究

对以乙酸木素(AL)为原料合成复合聚氨酯材料的方法及其特性进行了研究和探索。对乙酸法制浆废液的木素进行了提取和纯化,并采用红外光谱和GPC研究了乙酸木素的结构和分子质量。以乙酸木素代替部分聚乙二醇合成了AL-TDI-PEG复合聚氨酯,并对其进行了拉伸强度、最大伸长率、DSC和TGA热性能的测定和红外光谱分析,而且也对木素用量和这些物理性能之问的规律进行了研究和探索。实验结果表明,木素-TDI-PEG复合PU片具有较好的拉伸强度、伸长率和耐热性。当木素用量为20％时,强度达到最大,而超过20％时,强度有所降低,说明乙酸木素的加入对PU的强度有一定的影响。     

上油方式对锦纶6断裂强度的影响

测试了原油上油和乳液上油制得的锦纶6的断裂强度、密度和双折射率,分析了两种上油方式对锦纶6大分子结构的影响,并解释了原油上油比乳液上油所得到纤维强度高的原因。     

Molding polycarbonate: Moisture degradation effect on physical and chemical properties

Proper drying techniques prior to molding can eliminate the overall effects of moisture on the physicochemical properties of polycarbonate. Problems associated with moisture in polycarbonate during molding are described in detail. Moisture absorption is very rapid with the maximum allowable moisture content of 0.03 percent reached within 30 minutes at 49 percent RH and 75°F. Molding with excess moisture content causes a chemical and physical degradation resulting in reduction in tensile impact strength, tensile elongation, ultimate tensile strength, proportional limit and molecular weight. New and existing techniques and procedures for degradation detection were investigated, such as intrinsic viscosity, infrared spectrometry, and thermal methods of analysis. Gel permeation chromatography (GPC) proved the most satisfactory. GPC provided information on the average molecular weight and polydispersity.     

Bend Strength versus Tensile Strength of Fiber-Reinforced Ceramics

The bending strength of fiber-reinforced glasses and ceramics is often observed to be higher than their tensile strength; the difference varies, however, from one material to another. To gain an understanding of the relationship between these two measure of strength, we have carried out an analysis of bending which accounts for the deviations from linearity that occur on the tensile side of the beam. The results of this analysis indicate that the strength ratio (bending strength/tensile strength) depends most sensitively on the rate at which the stress drops after the ultimate tensile strength. In particular, composites failing gracefully (with a gradual decay in stress) tend to have comparatively higher strengths in bending. A method of inferring the: tensile strength from simply the load-deflection curve in bending is proposed. In addition, by accounting for the weakness in interlaminar shear, we can predict the variation in bend strength with beam aspect ratio. The various theories are compared with experimental data.     

A Generalized Relationship for Determination of Tensile Strength of Fine-Grained Soils from Shrinkage Characteristics

Tensile strength of fine-grained soils has been extensively investigated by earlier researchers and several methodologies have been evolved for its determination. However, either most of these methods are not valid/applicable for a wide range of moisture contents or they involve tedious sample/specimen preparation. In this context, the methodology of determining tensile strength by employing thin films, which is available in the literature, has been found to be quite handy and useful. It has been observed that a unique relationship exists among the tensile strength, moisture content, and shrinkage characteristics of fine-grained soils. This methodology is appreciable due to its applicability to a wide range of moisture contents, comparable ease of sample preparation and testing, and the obtained results lack generalization. Exhaustive tests were conducted on fine-grained soils of entirely different characteristics and generalized relationships have been proposed between the percentage linear shrinkage, tensile strength, and moisture content (defined as liquid to solid ratio). Based on a critical analysis of the results available in the literature, the efficiency of such relationships for determination of tensile strength of fine-grained soils has been demonstrated. In the authors’ opinion, such relationships would be quite useful for determining tensile strength of fine-grained soils from their linear shrinkage, which can easily be measured in a conventional geotechnical engineering laboratory.