纳米SiO_2包覆硅灰石粉填充改性聚丙烯的研究

通过实验制得纳米SiO2 包覆硅灰石粉 ,然后采用偶联剂进行表面处理。通过对聚丙烯(PP)的填充改性 ,将这一新型无机复合粉体与同样经偶联剂表面处理的传统的单一硅灰石矿物粉体填料进行了比较。结果表明 ,纳米SiO2 包覆硅灰石 ,填充改性聚丙烯 ,可同时达到增强、增韧的目的 ;且可大大提高填充量 ,从而降低产品成本。同时 ,从两相结合界面的结构形貌出发 ,解释纳米SiO2 包覆硅灰石粉在基体树脂聚丙烯中填充改性的作用机理     

聚丙烯/木质素复合材料制备及性能

采用溴代十二烷接枝改性木质素,提高其与聚丙烯的相容性,并以此为原料成功制备了木质素含量高达70%的聚丙烯/木质素复合材料。研究了溴代十二烷接枝改性木质素的结构及木质素掺量对聚丙烯/木质素复合材料的力学性能和流变性能的影响规律。结果表明,聚丙烯/改性木质素复合材料冲击强度和拉伸强度在木质素掺量低于10%时,随着木质素掺量的增大而提高,而断裂伸长率则明显下降。动态力学分析(DMA)表明,加入改性木质素可降低聚丙烯复合材料的玻璃化转变温度(Tg)。此外,复合材料的非牛顿指数随着改性木质素掺量的提高而增大,材料的加工性能改善。SEM分析显示,改性木质素与聚丙烯基体的界面结合较好。     

纳米SiO2包覆硅灰石粉填充改生聚丙烯的研究

通过实验制得纳米SiO2包覆硅灰石粉，然后采用偶联剂进行表面处理。通过对聚丙烯（PP）的填充改性，将这一新型无机复合粉体与同样经偶联剂表面处理的传统的单一硅灰石矿物粉体填料进行了比较。结果表明，纳米SiO2包覆硅灰石，填充改性聚丙烯，可同时达到增强、增韬的目的；且可大大提高填充量，从而降低产品成本。同时，从两相结合界面的结构形貌出发，解释纳米SiO2包覆硅灰石粉在基体树脂聚丙烯中填充改性的作用机理。     

稀土偶联剂WOT对PP复合材料老化性能的影响

通过高分子材料自然老化实验前后力学性能的变化,研究了稀土偶联剂WOT对PP／CaCO3、PP／Mg(OH)2、 PP／BaSO4复合体系的老化性能的影响。发现WOT对这三种填料均有良好的改性作用,体系的力学性能显著提高, 老化性能明显改善,填充量高时这种作用更加明显。老化180天后,WOT和CaCO3用量高的体系的冲击强度是纯 PP的2-2.4倍,性能保持率为66％-74％;WOT、和Mg(OH)2用量高的体系的冲击强度是PP的2.4-2.8倍,性能保 持率为77％-80％:WOT和BaSO4用量高的体系的冲击强度是PP的2.7-3.3倍,性能保持率为74％-91％。     

聚丙烯管材专用料的鉴别

聚丙烯管材专用料一般分为均聚聚丙烯(PP H)、嵌段共聚聚丙烯(PP B)及无规共聚聚丙烯(PP R)及改性PP H几种。本文将从结构与性能的角度出发,以透射、红外、差式扫描量热、核磁测试、热性能测试及力学测试为手段,详细讨论各种管材专用料的区别及鉴定方法。     

发泡聚丙烯在建筑材料中应用的研究

发泡聚丙烯材料具有强度高,可反复利用,保温性能高的特点,可作为环境友好材料使用。目前我国聚丙烯泡沫材料的研究尚处于起步阶段,其主要原因是适于聚丙烯(PP)发泡的温度区间窄,发泡过程较难控制。而提高PP发泡性能的关键在于提高体系在发泡时的熔体强度,主要采用直接使用高熔体强度PP、化学交联和接枝、共混改性等方法。文章对发泡聚丙烯的应用背景,发展现状和建材领域的应用进展进行了系统的分析和总结。     

聚丙烯/弹性体POE/纳米碳酸钙共混复合材料研究

采用双螺杆熔融共混法，以4种不同的混合方式，制备了配比为m(PP)：m(PoE)：m(nano-CaCO3)＝100：12：8的复合材料，研究了共混复合方式对材料力学性能及形态结构的影响。通过透射电镜(TEM)，熔体流动速率(MFB)及拉伸、弯曲冲击强度的分析测试，结果表明：各组分混合次序及PP受热过程的不同，复合材料的力学性能、加工流动性能存在明显的差异；纳米碳酸钙对聚丙烯(PP)、乙烯辛烯共聚物(POE)有一定的热稳定作用，与PoE一起对PP抗冲改性作用显著；纳米碳酸钙在PP和PoE相中的分配比及分散性是决定复合材料性能的主要因素。     

不同填料对阻燃聚丙烯复合材料燃烧性能的影响

以十溴二苯醚(DBDPO)、八溴二苯醚(OBDPO)、三氧化二锑(Sb2O3)为阻燃剂,滑石粉(Talc),蒙脱土(Mmt),凹凸棒(Atp),炭黑(CB)为填料熔融挤出制备阻燃聚丙烯复合材料。比较了两种溴系阻燃剂对PP性能的影响并研究了滑石粉,蒙脱土,凹凸棒三种不同的层状硅酸盐材料以及炭黑含量对OBDPO阻燃聚丙烯垂直燃烧性能,热稳定性的影响。研究表明,OBDPO复配阻燃剂含量为10wt%时PP/OBDPO/Sb2O3体系能达到UL94V-0级,且力学性能较优;Atp的阻燃协效率最高,3wt%的Atp就达到6wt%的Mmt和Talc阻燃协效率;3wt%的滑石粉和4wt%的CB能改善OBDPO阻燃聚丙烯复合材料的滴落情况,但是随着CB用量的增加,复合材料的燃烧加剧,且CB含量较高时,Talc的防滴落效果不明显。     

三聚氰胺聚磷酸盐抑制聚丙烯粉尘爆炸研究

利用20 L球形爆炸装置,试验研究了聚丙烯(PP)粉尘爆炸特性及三聚氰胺聚磷酸盐(MPP)对聚丙烯粉尘爆炸的抑制效果.结果表明,质量浓度为300 g/m3的聚丙烯粉尘爆炸强度最大,最大爆炸压力为0.746 MPa、最大爆炸压力上升速率为60.508 MPa/s、爆炸指数最大为16.398 MPa·m/s.随着MPP粉末...     

乙烯/辛烯共聚物(POE)改性沥青研究

比较了5种不同牌号乙烯/辛烯共聚物(POE)对沥青性能的改善效果,优选出最佳的POE改性剂;研究了不同加量的同种POE对沥青的改性效果;比较了相同加量下,POE、聚丙烯(PP)、聚乙烯(PE)改性沥青的性能指标。结果表明:POE能显著改善改性沥青的针入度、软化点和耐热性能等,较PP和PE对沥青的改性效果更为显著。     

Preparation and properties of a single molecule intumescent flame retardant

Melamine salt of pentaerythriol phosphate (MPP), as a new single molecule intumescent flame-retardant, was prepared from pentaerythritol, phosphoric acid, and melamine, and then incorporated into polypropylene (PP) with organic montmorillonite (OMT) to obtain flame retardant PP/MPP/OMT composites. The flammability and combustion behavior of flame retardant PP composites were characterized by using LOI, UL-94 test, and cone calorimeter, respectively. The results showed that the flame retardant properties of the composite containing 29.0 wt% MPP and 1.0 wt% OMT are the best among all the composites. The digital photographs after cone calorimeter test demonstrated that moderate OMT could promote to form the homogenous and compact intumescent char layer.     

钢丝网骨架塑料（聚乙烯）复合管安装工艺

分析了钢丝网骨架塑料（聚乙烯）复合管的连接原理,详细介绍了钢丝网骨架塑料（聚乙烯）复合管安装工艺,探讨了工程施工中的重点及难点,归纳了该连接工艺的优点,从而推广钢丝网骨架塑料（聚乙烯）复合管的应用。     

Assessment of glass fiber-reinforced polyester pipe powder in soil improvement

This study investigates the use of glass fiber-reinforced polyester (GRP) pipe powder (PP) for improving the bearing capacity of sandy soils. After a series of direct share tests, the optimum PP addition for improving the bearing capacity of soils was found to be 12%. Then, using the optimum PP addition, the bearing capacity of the soil was estimated through a series of loading tests on a shallow foundation model placed in a test box. The bearing capacity of sandy soil was improved by up to 30.7%. The ratio of the depth of the PP-reinforced soil to the diameter of the foundation model (H/D) of 1.25 could sufficiently strengthen sandy soil when the optimum PP ratio was used. Microstructural analyses showed that the increase in the bearing capacity can be attributed to the chopped fibers in the PP and their multiaxial distribution in the soil. Besides improving the engineering properties of soils, using PP as an additive in soils would reduce the accumulation of the industrial waste, thus providing a twofold benefit.     

In-plane shear behaviour of fibre composite sandwich beams using asymmetrical beam shear test

The in-plane shear behaviour of a new generation composite sandwich beam made up of glass fibre skins and modified phenolic core material was investigated to determine its application as shear loading component in a structural beam. Iosipescu shear test was conducted to characterise the shear properties of the fibre composite skins and the phenolic core material. The fibre composite sandwich beams were then tested under asymmetrical beam shear to determine its behaviour under in-plane shear loading. The results show that the in-plane shear behaviour of the composite sandwich beam is similar to that of the skins. A theoretical prediction of the in-plane shear strength of the composite sandwich beam was proposed and showed a good agreement with the experimental results. Based on the results of the study, the asymmetrical shear test is recommended as a test method for determining the shear properties of sandwich structures with high strength core materials.     

聚丙烯复合材料损伤本构模型的评估

玻璃纤维毡或短切纤维增强聚丙烯复合材料在交通领域可以替代钢材。基于模拟聚丙烯复合材料本构模型的破坏机制,评价了CODAM模型。首先,确定聚丙烯复合物CODAM模型中的参数;然后,通过有限元模拟与标准材料试验的相关性,确定受拉、受压和受剪破坏参数。标准材料试验包括拉伸、压缩、紧凑拉伸和剪切试验;通过冲击试验初步验证了模型的有效性。     

PP-R给水管道施工中应注意的若干问题

PP-R给水管道作为90年代开发的一种新型管材,在建筑给水工程上应用相当广泛。本文就PP-R给水管道的特点,从管材管件质量、管道敷设与连接、伸缩变形补偿措施以及管道试压检漏等方面进行探讨,提出施工中应注意的主要问题及其相应的技术措施。     

Experimental and numerical studies on the confined effect of steel composite circular columns subjected to axial load

For accurate analysis of steel composite circular columns, nonlinear material properties considering lateral confinement are required. Therefore, the material properties were modified after the experimental results from this study were compared with the results available in the literature. A nonlinear numerical analysis application, which can reflect and analyze the load-displacement, moment-curvature and P-M interaction, was developed on the basis of the modified stress-strain relation. The experimental results were compared with analysis results by using this application for concrete-filled tube (CFT) and concrete-encased tube (CET) circular columns. Results from the comparison show that the current code specifications are conservative because some of them do not consider the strength enhancement by the confined effect. This finding indicates the necessity to reflect nonlinear material properties considering the confined effect in the analysis of the composite columns.     

复合配筋预应力混凝土管桩抗弯性能试验和数值分析

开发研制了复合配筋(GFRP筋)预应力混凝土管桩(以下简称PRC-G桩),并进行了抗弯性能的现场抗弯试验和数值分析。试验研究结果表明,GFRP筋可以明显改善常规管桩的抗弯性能,其开裂荷载和极限荷载均有显著的提高,破坏时PRC-G桩均是受压区混凝土破碎而PRC桩的预应力筋被拉断;数值分析结果表明,PRC桩破坏时,预应力钢筋达到屈服强度1 420 MPa,PRC桩受压区混凝土未达到标准抗压强度,桩身未被破坏;PRC-G桩破坏时,受压区混凝土最大压应力为52.03 MPa,受压区混凝土破碎,管桩破坏。抗弯数值模拟和抗弯试验的结果表明,两者的荷载-挠度曲线的规律基本一致。研究成果可为复合配筋(GFRP筋)预应力混凝土管桩在工程中的推广应用提供理论依据。     

复掺纤维对RPC高温后力学性能及超声规律的影响

为了提高活性粉末混凝土(RPC)的力学性能并改善其高温爆裂性,在RPC中将0.3%、0.4%聚丙烯纤维(PP)和0、1%、2%、3%钢纤维(S)组合复掺,共设计8组试件,养护并模拟火灾试验,统计试件在高温(200、400、600℃)作用下的爆裂情况,研究复掺纤维对高温后RPC的抗折和抗压强度、强度损失率、折压比的影响,抗压强度、受火温度与超声波速的规律,确定两种纤维的最佳配合比。结果表明:掺入PP可以改善RPC高温爆裂;RPC抗折、抗压强度、折压比及超声波速随受火温度升高均呈先上升再下降的趋势,复掺入S可提升RPC的抗压、抗折强度和折压比;当S与PP掺量分别为1%与0.3%、2%、0.4%时,RPC未爆裂且强度较高,超声波速与抗压强度的相关性也较高。