酚酞基聚芳醚砜改性双酚A型氰酸酯预聚体的制备及性能研究

将酚酞基聚芳醚砜（PES-C）与双酚A型氰酸酯（BCE）共混,在一定的条件下使氰酸酯预聚,得到酚酞基聚芳醚砜与双酚A型氰酸酯共混改性预聚体系,借助FT-IR和DSC确定了固化工艺,并用扫描电镜（SEM）对预聚体及其固化物进行表征,测试了改性体系的冲击强度和对铝合金的粘接强度。结果表明,PES-C对CE起到了明显的增韧改性的作用,改性体系固化物具有较好的介电性能,在常温到230℃范围内粘接剪切性能优异（均大于20MPa）。该改性体系可用作一种新型耐高温结构胶黏剂的主体树脂。     

热塑性树脂增韧5405双马来酰亚胺树脂

为进一步提高５４０５双马来酰亚胺树脂的韧性，采用刚性热塑性树脂聚醚砜、酚酞聚芳醚砜、酚酞聚芳酮和端羟基酚酞聚芳醚酮作为增韧剂分别与其共混改性。结果表明，加入少量热塑性树脂进一步提高５４０５双马来酰亚胺树脂的韧性，同时不降低其耐热性，其中以低分子质量ＰＥＳ增韧效果最显著。     

杂萘联苯聚芳醚酮改性环氧树脂的结构与性能

采用新型耐高温高性能热塑性树脂杂萘联苯聚芳醚酮(PPEK)对环氧树脂(EP)进行共混改性.研究了共混物的结构和热力学性能,并对其增韧机理进行了分析.结果表明,EP/PPEK/4,4'-二氨基二苯砜共混物的热性能得到了提高而断裂韧性整体呈下降趋势.在添加15份PPEK时,共混物的临界应力强度因子(KIC)略有提高,即韧性...     

氯甲基化/季铵化新型聚芳醚砜酮超滤膜的研制

本文对含二氮杂萘结构聚芳醚砜酮进行改性制得氯甲基化聚芳醚砜酮。选用N-甲基一2-吡咯烷酮作制膜溶剂，依据正交设计方法制得了一系列氯甲基化聚芳醚砜酮超滤膜。考察了聚合物浓度、添加剂种类和添加量以及制膜蒸发时间等对膜性能的影响。将氯甲基化聚芳醚砜酮超滤膜浸入三甲胺溶液进行季铵化反应，得季铵化聚芳醚砜酮超滤膜。并考察了膜的抗污染性。     

聚芳醚酮的改性研究

综述了特种工程塑料聚芳醚酮改性研究的进展,主要介绍了聚芳醚酮结构改性的三大类方法:主链上引入其他基团、主链上引入大侧基及共聚改性。研究表明,通过结构改性可以在保持聚芳醚酮高的耐热性能和力学性能的基础上有效地改善其加工性能和在有机溶剂中的溶解性。同时简介了聚芳醚酮与聚酰亚胺、聚醚砜、聚苯硫醚等高性能树脂以及不同种类的聚芳醚酮间共混改性的研究状况。     

季铵型交联聚芳醚砜薄膜的制备及其性能研究

以甲基丙烯酸二甲氨基乙酯(DMAEMA)为铵化试剂,合成了含有双键的季铵型聚芳醚砜共聚物,通过流延技术,在热处理条件下挥发溶剂并交联,制备了季铵型交联聚芳醚砜(cPAES-N)薄膜。论文研究了聚芳醚砜的基本结构、交联情况、热稳定性和不同温度下的吸水溶胀情况。研究发现,交联聚芳醚砜薄膜可在流延溶剂中稳定存在,而且其热稳定性优于非交联聚芳醚砜(PAES-N);交联聚芳醚砜薄膜的吸水率与溶胀率均低于非交联聚芳醚砜薄膜,尺寸稳定性良好。     

回收PE/PET共混物的原位微纤化和反应增容研究

通过原位微纤化技术和反应增容,制备了含回收聚对苯二甲酸乙二醇酯(PET)、低密度聚乙烯(LDPE)和线性低密度聚乙烯(LLDPE)以及高密度聚乙烯(HDPE)的原位微纤化共混物(MRB).探讨了原位成纤作用下,相容剂马来酸酐接枝聚乙烯(PE-g-MAH)用量对共混物力学性能的影响,同时利用差示扫描量热仪(DSC)和扫描电镜(SEM)研究了含4份PE-g-MAH共混物的非等温结晶特性和共混物形态.结果表明,成纤和增容双重作用对共混物的拉伸强度、断裂伸长率、弯曲模量和弯曲强度都有提高,而冲击强度有所下降;微纤对基体聚乙烯结晶有促进作用且注塑共混物比拉伸共混物更明显.HDPE与LLDPE发生了共结晶;拉伸共混物中的微纤比注塑共混物中的微纤长.     

PPESK／PPS共混物流变性能的研究

以溶液共混－共沉淀的方式制备了含二氮杂萘联苯结构的聚醚砜酮／聚苯硫醚共混物，用毛细管流变仪考究了共混物的流变行为，讨论了剪切速率，温度和组成对体系流变性能的影响。结果表明，共混体系属于假塑性流体，少量聚苯硫醚的加入，可以明显降低体系的表观粘度，提高ＰＰＥＳＫ的加工性能。     

原位反应法制备聚乳酸/聚氨酯共混物及性能

以聚乳酸（PLA）、聚四氢呋喃醚二醇（PTMG）和液化4,4′-二苯基甲烷二异氰酸酯（L-MDI）为原料,通过原位反应法制备了PLA/聚氨酯（PU）共混物,研究了PLA/PU共混物的反应原理、力学性能、断面形貌、动态流变性能以及结晶性能。结果表明,在原位反应中有微交联结构PU生成,且伴随着PLA的扩链和枝化反应;PLA/PU共混物的韧性得到显著提高,当PU含量为30 %（质量分数,下同）时,共混物的断裂伸长率、断裂韧性和缺口冲击强度分别达到230 %、134.13 MJ/m3和34.19 kJ/m2,较纯PLA分别增加了16.6、8.1和11.1倍,此时拉伸强度仍保持在较高水平（49.7 MPa）;纯PLA和PLA/PU共混物熔体均为假塑性流体,共混物具有更高的储能模量和复数黏度;PLA/PU共混物比纯PLA的结晶速率高,晶体完善程度高。     

新型共聚芳醚砜改性环氧树脂的结构与性能研究

采用新型杂萘联苯共聚芳醚砜(PPBES)树脂对环氧树脂(EP)进行共混改性,研究了共混物的结构和性能,并对其增韧机理进行了分析。结果表明:采用PPBES改性EP后,在共混物韧性提高的同时,其玻璃化温度最多提高了30℃,且热稳定性得到了很好的保持。     

微细钢纤维对高弹性模量混凝土力学性能的影响

基于修正的Furnas堆积模型和骨料紧密堆积试验设计了一种高弹性模量混凝土,并利用微细钢纤维改善高弹性模量混凝土的韧性,研究了钢纤维体积掺量对骨料紧密堆积状态下混凝土流动性能、强度、弹性模量及弯曲韧性的影响规律。结果表明:采用紧密堆积骨料和适量微细钢纤维可以构筑高弹性模量韧性混凝土,其静弹性模量和动弹性模量最高分别可达50.15 GPa和53.23 GPa,断裂能可达5 680.45 N/m,残余弯曲韧度比从0增加到0.43;高弹性模量混凝土的流动性能随着钢纤维掺量的增加而降低,抗折强度、弹性模量及弯曲韧性则均随着钢纤维掺量的增加而增加,混凝土的抗压强度随着钢纤维掺量增加先增加后降低。在骨料紧密堆积状态下,综合考虑流动性能、力学性能和工程经济性,高弹性模量混凝土中微细钢纤维的合理掺量为0.4%(体积分数)。     

Elastomer-toughened poly(phenylene sulfide)

For use as electrical and electronics parts, or automobile and mechanical parts, toughened poly(phenylene sulfide) (PPS) is desired. For these applications, our investigation centered on improving the toughness of PPS and developing elastomer-toughened PPS and elastomer-toughened compounds of PPS. Using chemically treated PPS and an olefinic elastomer with a functional group, we developed elastomer-toughened PPS using a reactive processing method. In the PPS matrix, the elastomer is finely dispersed. While the notched Izod impact strength of the original PPS is about 1 kg · cm/cm. clastomer-toughened PPS has a notched impact strength around 50 kg · cm/cm. The notched fracture surface of elastomer-toughened PPS is observed using a scanning electron microscope. We concluded that the mechanism for the toughening is attributed to energy dissipation by matrix yield.     

PPS/PC共混物力学性能的研究

测量丁聚苯硫醚／聚碳酸酯（PPS／PC）二元共混物的力学性能，并考察了PC含量对PPS／PC／EP（环氧树脂）共混体系力学性能的影响。结果表明，加入适量的PC树脂，可在一定程度上改善PPS树脂的拉伸强度、拉伸断裂强度、弯曲强度和冲击断裂韧性。     

聚芳醚酮改性苯并恶嗪树脂动态冲击性能研究

以聚芳醚酮改性苯并恶嗪树脂为原材料,用动态数字化冲击仪测试了改性树脂浇铸体的冲击性能,获得了树脂体系的冲击力-位移-能量曲线、冲击功和冲击韧性,并用扫描电子显微镜对冲击断面进行了观察。结果表明,聚芳醚酮共混改性苯并恶嗪树脂体系在冲击破坏时的能耗以裂纹形成功为主,体系的冲击韧性值与冲击功的变化趋势相似;冲击断面整体上呈现河流状纹路,裂纹扩展路径上能有效阻隔裂纹发散的点或吸收能量的长条状碎小断面少,对整体韧性贡献较小。     

Improvement in interfacial shear strength and fracture toughness for carbon fiber reinforced epoxy composite by fiber sizing

Carbon fiber was sized by a thermoplastic polymer solution mixed with a compatible amine monomer. The effect of sizing agent on tensile strength was studied by single fiber strength testing. Interfacial properties of re‐sized carbon fiber/epoxy composite were investigated, with special emphasis on the improvement in both interfacial shear strength and interfacial fracture toughness. The interfacial fracture toughness of composites was characterized by calculating the effective interphase fracture energy rate through the information obtained from the force–displacement curve in the micro‐bond test. Fracture topography of micro‐bond specimen was observed to discuss the interfacial fracture mechanism. POLYM. COMPOS., 35:482–488, 2014. © 2013 Society of Plastics Engineers     

Plane strain fracture toughness of polyphenylene sulfide

The plane strain fracture toughness of polyphenylene sulfide (PPS), tested with different molecular structures such as linear PPS, heat-treated PPS, and branched PPS, was investigated over a wide range of melt viscosity and crystallinity and compared with other mechanical properties. The fracture toughness of linear PPS increased with increasing melt viscosity, and it reached the highest fracture toughness calculated from linear elastic fracture mechanics (LEFM) observed in this study. In this high melt viscosity region, the linear PPS specimen showed slow crack growth instead of brittle fracture. Although the tensile properties of heat-treated PPS and branched PPS are the same as those of linear PPS, the fracture toughness of linear PPS is superior. The fracture toughness is affected by the crystallinity of the specimen, and the effect of crystallinity on fracture toughness is smaller than that of melt viscosity and molecular structure.     

Fracture behavior of glass bead-filled poly(oxymethylene) injection moldings

The mechanical properties of glass bead filled poly(oxymethylene) were investigated as a function of glass bead content and glass bead diameter using injection molded test pieces. Fracture toughness measurements were made using single edge-notched tension and single edge-notched bend specimens. The effect of notch orientation with respect to the mold fill direction on fracture toughness was studied using single gate and double gate moldings. Tensile strength and flexural modulus were measured using standard test pieces. It was found that; (i) fracture toughness of the filled and unfilled polymer was relatively independent of notch orientation, (ii) the presence of weldlines in the molded test pieces did not affect the fracture toughness of unfilled polymer or its composites, (iii) fracture toughness of filled polymer was always considerably lower than that of the unfilled polymer; fracture toughness decreased sharply with increasing bead concentration, (iv) fracture toughness was not a sensitive function of glass bead diameter; it decreased slightly as bead diameter increased, (v) strain energy release rate as measured under impact decreased with increasing bead concentration, (vi) tensile strength decreased linearly with increasing glass bead concentration and was inversely proportional to the square root of the bead diameter, (vii) weldlines did not affect the tensile strength of the polymer or its composities, (viii) flexural modulus increased linearly with increasing glass bead concentration according to the Einstein equation.     

Epoxy-functionalized polysiloxane reinforced epoxy resin for cryogenic application

The poor cryogenic mechanical properties of epoxy resins restrict their extensive application in cryogenic engineering fields. In this study, a newly synthesized epoxy-functionalized polysiloxane (PSE) is used to improve the cryogenic mechanical properties of bisphenol-F epoxy resin. The Fourier transform infrared spectra and nuclear magnetic resonance confirm the formation of epoxy-functionalized –Si–O–Si– molecular chain. The surface free energy test results show that the PSE has a better compatibility with epoxy resin. The mechanical test results show that the cryogenic tensile strength, failure strain, fracture toughness, and impact strength of epoxy resin is improved significantly by adding the suitable amounts of PSE. Compared to the neat epoxy resin, the maximum tensile strength (196.92 MPa, an improvement of 11.2%), failure strain (2.97%, an improvement of 33.8%), fracture toughness (3.05 MPa·m^1/2, an improvement of 30.7%) and impact strength (40.55 kJ m⁻², an improvement of 14.8%) at cryogenic temperature (90 K) is obtained by incorporating 10 wt % PSE into the neat epoxy resin. Moreover, the results also indicated that the tensile strength, Young's modulus, and fracture toughness of epoxy resin with the same PSE content at 90 K are higher than that at room temperature (RT). © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46930.     

简支梁冲击强度的测定

简支梁冲击强度是塑料力学性能的重要指标之一,塑料材料冲击强度是工程塑料机械强度设计的依据,它反映材料在高速载荷下的韧性或对断裂的抗冲击能力,因此测量简支梁冲击强度就有重要的意义。由于简支梁冲击试验是测试试样破坏时单位面积所吸收的能量,因此影响因素很多。采用注塑成型方法和机械加工方法制备煤基高密度聚乙烯产品试样,对测定过程和影响因素进行了探讨得出了最优化的实验参数。     

Preparation and properties of nanocomposite of poly(phenylene sulfide)/calcium carbonate

Summary A way to prepare Poly (phenylene sulfide) (PPS) nanocomposite was introduced in the paper. The nanocomposite of PPS/CaCO₃ can be prepared by melt mixing process. The dispersion of the CaCO₃ nanoparticles in PPS was good when filler content below 5 wt %. Differential scanning calorimeter (DSC) and small-angle light scattering (SALS) results indicated that the CaCO₃ nanoparticles could induce the nucleation but retard the mobility of polymer chains. The results of mechanical tests showed that a small amount of nanoparticles has resulted in a slight improvement in the tensile strength and a significantly 300% increase in the fracture toughness. We believe that the CaCO₃ nanoparticles can act as stress concentration sites, which can promote cavitation at the particles boundaries during loading. The cavitation can trigger mass plastic deformation of the matrix, leading to much improve fracture toughness.