玻纤增强酚醛注塑料的制备技术和性能

研究了玻纤增强酚醛注塑料制备过程中基质树脂的选择、固化作用与交联结构的控制及玻纤分散技术,考察了不同基质树脂制备的酚醛注塑料的固化成型结构形态和固化流变特性.进一步采用热固性与热塑性酚醛树脂相复配的基质树脂体系,经配方和制备工艺的优化,制备了高填充量玻纤增强酚醛注塑料.该注塑料具有良好的注塑成型性能,注塑制品具有高强度, 冲击强度达到4.3 kJ•m^-2,弯曲强度137.4 MPa,同时热变形温度为 245 ℃,阻燃性通过美国UL 94 V-0级认证,并具有优良的尺寸稳定性、电绝缘性能和低成本优势.     

高流动性快速固化酚醛注塑料的研制

介绍了一种高流动性快速固化酚醛注塑料的配方、制备工艺及其成型时间和流动特性。采用高邻位酚醛树脂为基质，复配复合稳定剂，优化辊炼工艺，制备了高流动性快速固化酚醛注塑料。该注塑料具有优异的流动性能，同时可快速成型，且不损失酚醛注塑料固有的力学性能、热性能及电性能。     

注塑型酚醛模塑料热加工稳定性研究

讨论了低相对分子质量聚乙烯蜡、白油、切片石蜡及聚乙二醇4种稳定剂对酚醛注塑料热加工稳定性的影响，重点利用转矩流变仪研究了聚乙二醇加入前后酚醛注塑料的流变行为。结果表明：低相对分子质量聚乙烯蜡、白油、切片石蜡及聚乙二醇都可以有效地改善酚醛注塑料的流动性和热加工稳定性，但只有聚乙二醇不仅改善了酚醛注塑料的流动性和热加工稳定性，丽且还提高了酚醛注塑制品的弯曲强度。转矩时间流变曲线表明，加入聚乙二醇后酚醛注塑料具有更加宽泛的安全加工范围。     

高外观热稳定性酚醛注塑料的研制

介绍了一种高外观热稳定性酚醛注塑料的配方、制备工艺及其性能。以热固性液体酚醛树脂和热塑性固体酚醛树脂相结合为主要基质，添加高填充量的短切玻璃纤维，并引入特种超细矿物质填料，采用复配的固化体系，应用界面改性技术并经特殊的混和、分散和塑炼工艺，制备了高外观热稳定性酚醛注塑料。该注塑料具有优秀的高温外观热稳定性能，由通常的低于300℃(2h)，提高到300℃(2h)和370℃(1h)，并具有优良的尺寸稳定性、电绝缘性能、力学性能以及注塑性能.     

一种换向器用酚醛注塑料

本发明公开了一种换向器用酚醛注塑料，该酚醛注塑料由以下质量份的组分组成：酚醛树脂100份，DOPO 改性环氧树脂10～20份，固化剂10～20份，耐电弧改性剂5～10份，潜伏性固化剂5～10份，玻璃纤维140～180份，脱模剂3～8份。该酚醛注塑料与换向器的铜排之间具有良好的粘结性，同时具有良好的力学强度、耐电弧性能及阻燃性，并且适用于快速注塑成型工艺。     

抗冲PVC注塑料的加工工艺

在普通PVC注塑料注塑工艺参数的基础上,对抗冲PVC注塑料的注塑温度、注塑压力、储料参数、注塑速度和模具温度等注塑工艺参数进行调整,初步得出了抗冲PVC注塑料的注塑工艺参数,并针对出现的"花斑"问题进行了分析、讨论。     

固体废弃塑料挤注压一体化设备的研发

提出挤注压一体化技术,采用新型肘杆直压复合式二次合模机构,利用二次压缩成型工艺解决了废弃塑料熔融料含气量大、流动性差等特性引起的注塑问题,提高了注塑制品的成型精度及质量;同时,利用连接装置完成“连续”挤出与“间歇”注塑压缩工作方式之间的协调与自动衔接,实现了固体废弃塑料到制品的直接转换。固体废弃塑料挤注压一体化设备的应用,在降低处理成本的同时极大地提高了固体废弃塑料回收再利用比例,实现了固体废弃塑料的高效处理与高值化再利用。     

酚醛树脂注塑固化成型及流动特性的研究

考察了辊压工艺及酚醛树脂的邻对位比值(O／P)对酚醛注塑料的成型时间及流动性的影响。结果表明注塑料的辊炼温度及时间对其成型时间及流动性有明显的影响，其中流动性受影响的幅度随树脂O／P值的不同而差别较大。O／P值愈高，流动性随辊压温度或辊压时间的增加而降低的趋势愈明显，成型时间随辊压温度或辊压时间的增加而缩短，但缩短的幅度受树脂O／P值改变影响较小。在不同O／P值酚醛树脂注塑料的各自最佳辊压工艺的条件下，影响注塑料成型时间的最关键因素是酚醛树脂的O／P值，O／P值愈高，成型时间愈短，而O／P值对注塑料的流动性的影响不明显。     

VARTM用酚醛树脂的化学流变特性及模型分析

研究了一种新型的用于真空辅助树脂传递模塑成型工艺(VARTM)酚醛树脂的流变特性。根据实测等温粘度曲线,采用双阿累尼乌斯模型,建立了用于真空辅助树脂传递模塑成型工艺(VARTM)酚醛树脂的化学流变特性模型方程,分析表明模型拟合与实验结果之间具有较好的一致性,这为有效地预测RTM树脂的低粘度工艺窗口、合理制定复合材料成型工艺参数提供了必要的科学依据。     

双组份注塑新技术

双组份注塑新技术据报道，利用美国道塑料公司新开发并已形成专利技术的供料头，塑料加工者可以直接注塑两种不同的树脂进入模具，且产品质量好．该工艺称为层状注塑，简称ＬＩＭ．它与标准注塑工艺相比，其优点为：产品阻隔性、耐溶剂性、光学透明性优良，操作周期短，并...     

风电叶片VIMP用环氧树脂体系流变性能研究

对两种风机叶片真空导入模塑(VIMP)工艺用环氧树脂体系的流变性能进行了研究,在黏度实验的基础上,依据双阿累尼乌斯方程建立了与实验数据较为吻合的流变模型.结果表明,两种树脂体系的黏度变化略有差异,在25～ 55℃的范围内,其黏度都低于500 mPa·s,且低黏度保持时间大于30 min,符合风机叶片VIMP工艺对树脂低...     

风机叶片用环氧树脂体系流变性能研究

本文对风机叶片用环氧树脂体系的流变性能进行了研究,在粘度实验的基础上,依据双阿累尼乌斯方程建立了与实验数据较为吻合的流变模型。结果表明,两种树脂体系的粘度随温度变化情况基本一致,在23～50℃范围内,其粘度都低于300mPa.s,且低粘度保持时间大于30min,符合风机叶片真空成型对树脂低粘度的要求。所建立的粘度模型可有效预测和模拟树脂体系在不同工艺条件下的粘度行为,揭示树脂体系的优化工艺参数和低粘度平台工艺窗口,为合理拟订工艺参数和保证产品质量提供必要的科学依据。     

Rheological modeling and finite element simulation of epoxy adhesive creep in FRP-strengthened RC beams

We have shown that a significant creep occurs at the concrete–fiber reinforced polymer (FRP) interface based on double shear long-term test. The primary test parameters were the shear stress to ultimate shear strength ratio, the epoxy curing time before loading as well as the epoxy thickness. The test results showed that when the epoxy curing time before loading was earlier than seven days the shear stress level significantly affected the long-term behavior of epoxy at the interfaces, and in particular the combined effect of high shear stress and thick epoxy adhesive can result in interfacial failure if subjected to high-sustained stresses. In this paper, based on the previous experimental observations, an improved rheological model was developed to simulate the long-term behavior of epoxy adhesive at the concrete–FRP interfaces. Furthermore, the newly developed rheological creep model was incorporated in finite element (FE) modeling of a reinforced concrete (RC) beam strengthened with FRP sheets. The use of rheological model in FE setting provides the opportunity to conduct a parametric investigation on the behavior of RC beams strengthened with FRP. It is demonstrated that creep of epoxy at the concrete–FRP interfaces increases the beam deflection. It is also shown that consideration of creep of epoxy is essential if part or the entire load supported by FRP is to be sustained.     

RFI成型工艺中渗透率的研究及树脂流变模型的建立

渗透率测量是树脂膜熔渗(RFI)工艺在复合材料设计和优化中最关键的条件。随着纤维体积分数的增加,渗透率非线性降低,可见纤维体积分数的变化对整个树脂体系浸渍纤维预制体有很大的影响。在黏度实验的基础上,对用于RFI工艺的环氧树脂体系的化学流变特性进行研究,并根据双阿累尼乌斯方程建立树脂体系的流变模型,为合理地制定RFI工艺参数、保证产品质量和实现工艺参数的全局优化提供科学依据。     

双组分豆粕基胶黏剂的流变行为研究

以改性胶液作为组分1,豆粕粉作为组分2,通过常温复配的技术手段制备了一种双组分豆粕基胶黏剂,并利用旋转流变仪对其流变行为进行了研究。结果表明：添加改性胶液的双组分豆粕基胶黏剂黏度增加,但剪切变稀现象与添加自来水的豆粕基胶黏剂保持一致;豆粕粉添加量对胶黏剂在高剪切速率下的流变行为的影响较为明显;Z试剂对胶黏剂在低配比（豆粕粉添加量≤10%）、低剪切速率（≤500 s^-1）下的流变行为影响较大;填料和表面活性剂只影响豆粕基胶黏剂的黏度而不改变其剪切流变行为。     

Application of degradation kinetics to the rheology of poly(hydroxyalkanoates)

The time‐dependent rheological behavior of a series of 3‐hydroxybuytrate‐based semicrystalline copolymers is employed to determine the expected rheological curves that would be generated in the absence of any polymer degradation. Both dynamic frequency sweep and shear rate sweep experiments were analyzed. A model for the degradation kinetics, coupled with standard rheological relationships, was employed to extrapolate the measured sweeps to predicted curves at time zero, prior to degradation. The model is broadly applicable over a wide range of frequencies or shear rates, and generates a single degradation rate constant k for each polymer studied. A similar, although ad hoc, procedure was applied to the dynamic storage and loss moduli. The model provides a method for determining the rheological behavior of degrading polymers over a time interval, typically found in processing applications. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:1794–1802, 2006     

Rheological studies on the phase dissolution in a block copolymer

The microphase transition in a styrene-butadiene-styrene triblock copolymer was studied by rheometric mechanical spectroscopy. A high-temperature-melt rheological transition from the highly elastic, nonlinear viscous behavior typical of a multiphase structure to linear viscous behavior with insignificant elasticity typical of a single-phase structure was observed. The transition temperature is determined according to the discontinuity of the rheological properties across the transition region, which agrees well with the results obtained from the small angle X-ray scattering data and the expectation of the random phase approximation theory. Maybe for the first time, microphase dissolution was investigated rheologically. The storage modulus (G′) and the loss modulus (G′) increase with time during the process. An entanglement fluctuation model based on the segmental density fluctuations is presented to explain the rheological behavior in this dissolution process. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1155–1164, 1997     

VARTM用EP体系流变特性及固化工艺的研究

研究了真空辅助树脂传递模塑(VARTM)工艺用环氧树脂(EP)体系的流变特性,结合差示扫描量热(DSC)仪和旋转式粘度计对A1、A2、A3三种EP体系的测试结果,确定A2树脂体系适合于VARTM工艺,并根据双阿累尼乌斯方程,建立了A2树脂体系的流变模型。该模型可以预测树脂在不同温度下的粘度特性,为合理制定工艺参数提供了重要依据。用DSC仪对A2树脂体系的固化反应过程进行分析,利用外推法确定了固化工艺参数。     

粒度分布对超低水泥刚玉质浇注料流变性的影响

用浇注料流变仪研究了粒度分布对超低水泥刚玉质浇注料流变性的影响。结果表明 :粒度分布对超低水泥浇注料的流变性影响较大。随着粒度分布系数 (q)的减小 (从 0 .2 9、0 .2 6到 0 .2 3) ,浇注料的剪切应力、粘度和屈服应力增加 ,需水量上升 ,说明流变性变差。以 2 %的SiO2 微粉等量替代q =0 .2 3的浇注料中的Al2 O3微粉后 ,试样的流变性得到明显改善 ,更适合用于泵送施工 :浇注料的需水量减少 ,自流值提高。     

Mechanical behavior of a semicrystalline polymer before necking. Part II: Modeling of uniaxial behavior

Based on the experimental mechanical characterization presented in Part I of this paper, a model allowing the prediction of the behavior of the studied semicrystalline polymer in the pre‐necking domain was constructed. The modeling of the viscoelastoplastic behavior of polypropylene (PP) was described by partitioning the total strain into a viscoelastic strain and a viscoplastic strain. After being improved with experimental observations, the rheological model of Zener was used to model the viscoelastic behavior of PP. As for viscoplastic behavior modeling, it was based on the characterization of the mechanical behavior performed in the first part of the study. Attention was focused on the strain reversal in order to predict the unloading path. Experimental data from the performed mechanical tests were employed to determine the parameters of the viscoelastoplastic model.