浅析PVC板材热转印技术

探讨PVC板材热转印技术的生产原理与流程、生产设备、热转印膜。分析了生产中的技术要点,并提出了解决的办法。     

涂覆聚氨酯的聚酯/氨纶复合织物的定量分析研究

研究了涂覆聚氨酯(PU)的聚酯/氨纶复合织物(简称PU涂层复合织物)的定量分析方法,探讨了以四氢呋喃和环己酮作为溶剂在不同温度条件下对去除PU涂层复合织物中的PU涂层的效果,对去除PU涂层后的PU涂层复合织物进行其中的聚酯纤维含量(G)的测定并分析了未涂覆PU的相应聚酯/氨纶复合织物中的聚酯纤维含量(G0).结果表明:...     

美式落锤冲击试验在PVC-U异型材冲击性能评价中的应用

介绍了采用美式落锤法对PVC-U异型材的冲击性能进行量化评价的试验方法。结果表明,美式落锤冲击试验受很多因素(如温度、试样尺寸和试样的成型工艺)影响。     

Influence of compatibilizer on notched impact strength and fractography of HDPE–organoclay composites

The focus of this study was the notched impact property of high‐density polyethylene (HDPE)–organoclay composites and the resultant morphology of impact‐fractured surfaces. Composites with a different organoclay content and degree of organoclay dispersion were compared with neat HDPE under identical conditions. The degree of organoclay dispersion was controlled through the use of a compatibilizer, maleic anhydride grafted polyethylene. It was found that the addition of organoclay can slightly increase the elastic modulus and notched impact strength of the composite. When the level of organoclay dispersion was improved by using compatibilizer, elastic modulus and toughness further increased. A significant increase in yield strength was also notable. The presence of organoclay was found to suppress strain hardening of the matrix during tensile testing. The impact‐fractured surfaces of failed specimens were studied with scanning electron microscopy. The micromechanism for the increased toughness of HDPE–organoclay composites was discussed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Variable temperature and stretching cell for Raman spectroscopy studies of polymers

A variable temperature cell for use in laser spectroscopy studies of polymers and for the drawing of compounds is described. ‘In situ’ polarized Raman spectra of polyethylene at different draw ratios and different temperatures are recorded. The depolarization factors allow assignment of the vibrational types to the Raman active modes and the chain orientation study.     

Preparation of pigment–polymer hybrid particles for plastic colorants by dry‐impact blending method

Dry‐impact blending method was employed to prepare hybrid particles composed of fine particles of phthalocyanine blue and a coarse particle of low‐density polyethylene (LDPE). A simple mixing in a Henschel‐type batch mixer of the two kinds of particles, which were largely different in the size, in ambient temperature applying high stress, produced hybrid particles, where the fine particles are distributed on the surface of the core particle. The surface appearances and the cross‐sectional views of the particles were observed by scanning and transmission electron microscopy. It was revealed that the hybrid particles exhibited a capsule formation with the LDPE core coated with the phthalocyanine layer, where the phthalocyanine fine particles were embedded in the LDPE core particles. The hybrid particles thus prepared helps fine dispersion of the pigment into the LDPE matrix, and the pigmented LDPE sheet shows excellent color quality. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1762–1772, 1999     

超高分子量聚乙烯/高密度聚乙烯共混物的低温冲击研究

通过DSC、SEM和动态流变法分析超高分子量聚乙烯/高密度聚乙烯(UHMWPE/HDPE)共混物的相容性。结果表明:UHMWPE和HDPE具有良好的相容性。UHMWPE/HDPE共混物是典型的假塑性流体,当HDPE的质量分数逐渐增大,共混物的复数黏度明显减小,其流动性变好。UHMWPE能够显著提高共混物的低温冲击性能,当UHMWPE含量超过40%,共混物在-60℃的缺口冲击强度在70 kJ/m²以上。当UHMWPE含量为50%,共混物的熔体流动速率为0.12 g/10min,-60℃缺口冲击强度达到77 kJ/m²,使加工性和低温冲击性能达到平衡。     

ABS树脂冲击强度测试的影响因素

对比了4个牌号ABS树脂ASTM标准和国标悬臂梁冲击强度,剖析了ABS树脂橡胶相组成对测试结果的影响,并运用moldflow软件模拟冲击样件注塑成型过程,分析引起冲击强度测试结果差异的原因.结果表明,通过降低冲击测试样条注塑成型注塑速度减小样件表面剪切应力的方法,能够提高冲击强度测试结果,较高的橡胶含量可以减弱注塑速度...     

A further study of factors affecting pneumatic‐impact ignition of polymers

One likely cause of polymer ignition in high‐pressure oxygen systems is the adiabatic‐compression heating of polymers caused by pneumatic impact. The previous study showed that pneumatic‐impact ignition of polymers could be initiated by a local heterogeneous reaction between the hot oxygen and the oxidation sites of the polymer. This study further investigates other factors that cause pneumatic‐impact ignition of polymers in high‐pressure oxygen. Because the oxygen concentration has a significant effect on pneumatic‐impact ignition, threshold oxygen concentrations for pneumatic‐impact ignition of six selected polymers were determined at 20.7 MPa (3000 psia), an expected service pressure in high‐pressure oxygen systems. The six polymers investigated were: Teflon PTFE (polytetrafluoroethylene), Neoflon CTFE (polychlorotrifluoroethylene), PEEK (polyetheretherketone), Zytel 42 (nylon 6/6), Buna N (acrylonitrile butadiene rubber), and Viton A (copolymer of vinylidene fluoride and hexafluoropropylene). The results show that PEEK exhibited the highest threshold oxygen concentration (65%) and Zytel 42 exhibited the lowest threshold oxygen concentration (<21%). Copyright © 2006 John Wiley & Sons, Ltd.     

Mechanical impact tests of some selected polymers in high pressure liquid oxygen environments

The threshold impact energies of the liquid oxygen mechanical impact test were determined for eight polymers at 6.9 MPa (1000 psi) oxygen pressure. The results show that there was no correlation between the threshold impact energy and the autoignition temperature of the polymers in high pressure oxygen environments. A violent explosion was observed in some of the tests when nylon 6/6, nitrile rubber and polyurethane rubber were impacted in high pressure liquid oxygen. Copyright © 2004 John Wiley & Sons, Ltd.     

无规共聚聚丙烯管材氧化诱导时间测试探究

以无规共聚聚丙烯（PP?R）管材为研究对象,采用差示扫描量热仪（DSC）测试了PP?R管材的氧化诱导时间（OIT）,并研究了测试部位、样品直径、样品厚度以及取样方式等测试条件对OIT测试结果的影响。结果表明,从垂直管壁方向取芯层直径为6 mm、厚度为650 μm的试样进行测试时,OIT测试结果相对可靠。     

Pneumatic impact ignition of selected polymers in high‐pressure oxygen environments

One likely cause of polymer ignition in high‐pressure oxygen systems is adiabatic‐compression heating of polymers, caused by pneumatic impact. This study investigates ignition by pneumatic impact of selected polymers in high‐pressure oxygen environments. Six polymers commonly used in high‐pressure oxygen systems were tested in a pneumatic‐impact test system at 8.3–37.9 MPa oxygen pressures. The six polymers tested were Teflon^®(polytetrafluoroethylene), Neoflon^®(polychlorotrifluoroethylene), PEEK (polyetheretherketone), Zytel^® 42 (Nylon 6/6), Buna N (nitrile rubber), and Viton^® A (copolymer of vinylidene fluoride and hexafluoropropylene). This study shows that the ignition of polymers due to pneumatic impact could be initiated by a local heterogeneous reaction between the hot oxygen and the oxidation sites of the polymer, and proposes an ignition mechanism. Ignition susceptibility of a material to the pneumatic impact can be expressed by its ignition probability. The ignition probabilities of the six polymers at the various oxygen pressures are presented. There is no good correlation between the ignition probability and the autoignition temperature. Copyright © 2006 John Wiley & Sons, Ltd.     

利用煤矸石制砖的环境影响分析

以晋城康厦建材有限公司的煤矸石砖生产线为例,探讨了利用煤矸石制砖可能造成的环境影响,并针对采取的防治措施进行了评价,肯定了此工艺的可行性。     

透明高抗冲聚苯乙烯树脂的工业化试验

在5kt／a高抗冲聚苯乙烯树脂装置上,以1,1-双(叔丁基过氧基)环己烷为引发剂、苯乙烯为单体、丁二烯-苯乙烯嵌段共聚物(简称K树脂)为增韧剂,采用自由基聚合工艺生产了透明高抗冲聚苯乙烯(HT-IPS)树脂,考察了HT-IPS树脂的微观结构、相对分子质量及其分布、流变性能、接枝反应程度、物理机械性能和光学性能,讨论了影响HT-IPS树脂结构及性能的因素。结果表明,HT-IPS树脂具有微观相分离结构,聚丁二烯链段为分散相、聚苯乙烯链段为连续相;HT-IPS树脂的流动性能略差于高抗冲聚苯乙烯树脂,且随着K树脂用量的增加,其流动性能变差,K树脂用量应控制在15份以下;在聚丁二烯链段的主链和侧链均发生了接枝反应,HT-IPS树脂具有较高的弯曲强度、弹性模量和拉伸强度,其光学性能、流变性能良好,但冲击强度较低,扯断伸长率较小。     

Structural changes of bulk polyethylene by stress impact as studied by solid‐state NMR

Solid‐state ¹³C‐ and ¹H‐NMR spectra of bulk high‐density polyethylene samples, cylindrical in form, to which stress impacts were applied with a home‐made stress‐impact apparatus, were measured. The fraction of the noncrystalline component increases with an increase in the stress‐impact strength. In the crystalline region, the monoclinic crystalline component appear with the stress impact, in addition to the major orthorhombic crystalline component. Furthermore, dynamic characterization was carried out on the basis of the observed values of the relaxation parameters ¹H T₂ and T_CH of the ¹H and ¹³C nuclei. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2268–2272, 2001     

Study on phase behavior–impact strength relationship of unsaturated polyester/polyurethane hybrid polymer network

The phase behavior of a hybrid polymer network (HPN) composed of poly[(propylene glycol maleate)-co-(propylene glycol phthalate)] crosslinked with styrene and polyester–urethane crosslinked with methylene-bis-ortho-chloroaniline was examined. The correlation between phase separation and impact strength of the HPNs is discussed. The composition of HPNs has an effect on their properties.     

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.     

Development of a modified test cell for AC impedance testing of coated Al fins

An innovative test-cell arrangement is proposed and examined for electrochemical impedance spectroscopy (EIS) testing of coated thin sheet or foil samples. This arrangement uses a thin layer of medical cotton fabric as a medium containing and transporting 5% sodium chloride solution. This new EIS cell avoids the intervention of edge effect into EIS measurements of painted material. It also avoids the formation of crevice attack experienced at the edges of conventional sample holders or normally under the edge of the masking material. This arrangement is simple and flexible to suit different sizes and shapes of flat panel and foil samples. It can also be used effectively as specimen holders for other than thin sheets. The test cell is also suitable for any electrochemical tests other than impedance measurements. The accelerated results of the EIS present the viability of the EIS test cell to be used as an accelerated nondestructive, repetitive measurement of coated thin metal substrate.     

Mechanical behavior and failure analysis of recycled polymers by use of miniature punch specimens

In today's society, recycling is a priority, and using recycled materials to obtain new 100% reusable materials is an important aspect of some manufacturing sectors. Clearly, the mechanical properties of these new materials can vary considerably from the original material, so it is necessary to carry out a complete mechanical characterization to know its behavior for both standard specimens and final components. One of the common drawbacks is the inability to extract standard size specimens from a final component with a reduced size. In this paper, the use of the small punch test is proposed as a means of solving this problem. At present, this test is used for estimating mechanical properties in those cases when there is not a sufficient amount of material to perform standard tests. The main purpose of this paper is to analyse the feasibility of using miniature punch specimens for the mechanical characterization of recycled polymers. The results are compared with those obtained from standard uniaxial tensile specimens, and a corresponding correlation between the two tests is established. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42911.