PP镁盐晶须复合材料的性能研究

研究了镁盐晶须填充改性聚丙烯(PP)材料的力学性能以及PP-g-MAH和PP-g-GMA为相容剂对复合材料的影响等.结果表明:镁盐晶须能明显改善PP材料的拉伸强度、弯曲强度和弯曲模量等力学性能;PP-g-MAH和PP-g-GMA作为相容剂改善镁盐晶须对PP的增韧补强作用.     

纳米Mg(OH)_2-微胶囊红磷/乙烯-乙酸乙烯酯共聚物阻燃复合材料的性能

以微米Mg(OH)_2(mMg(OH)_2)、纳米Mg(OH)_2(nMg(OH)_2)和微胶囊红磷(MRP)为无卤阻燃剂,乙烯-乙酸乙烯酯共聚物(EVA)为聚合物基体,通过熔融共混方法制备了一系列不同阻燃剂含量的Mg(OH)_2-MRP/EVA阻燃复合材料,采用极限氧指数、垂直燃烧、锥形量热分析、热分析、SEM、拉伸试验、流变学分析等方法研究了复合材料的阻燃、力学和加工性能。结果表明,Mg(OH)_2阻燃剂用量相同时,nMg(OH)_2/EVA复合材料的阻燃和抑烟性能比mMg(OH)_2/EVA复合材料更好,但当Mg(OH)_2用量小于60wt%时,nMg(OH)_2/EVA和mMg(OH)_2/EVA复合材料的垂直燃烧等级都达不到V-0级。Mg(OH)_2本身的阻燃效率较低,nMg(OH)_2和MRP对EVA有非常显著的协同阻燃作用,二者掺杂比例适当时可大幅度降低Mg(OH)_2的用量。与nMg(OH)_2/EVA复合材料相比,nMg(OH)_2-MRP/EVA复合材料燃烧时能够生成连续致密的炭层,覆盖在材料表面形成防火屏障,提高其阻燃性能。nMg(OH)_2的热分解反应对nMg(OH)_2-MRP/EVA复合材料的燃烧性能有极其重要的影响。当nMg(OH)_2热分解后再加入到MRP/EVA体系中时,nMg(OH)_2-MRP/EVA复合材料的阻燃和抑烟性能均急剧降低。当nMg(OH)_2∶MRP∶EVA的质量比为40∶10∶100时,nMg(OH)_2-MRP/EVA复合材料同时具有优异的阻燃性能、力学性能和加工性能,可满足实际应用的需要。     

胶原蛋白/低密度聚乙烯复合材料的制备与性能

为了探讨胶原蛋白（HC）和相容剂马来酸酐接枝低密度聚乙烯（LDPE-g-MAH）对聚合物材料性能产生的影响,以低密度聚乙烯（LDPE）为基体,用共混挤出的方法制备了HC/LDPE复合材料和HC/LDPE-MAH复合材料,并将复合材料注塑成不同规格样条。通过力学性能测试、SEM和热分析等表征方法研究了HC和LDPE-g-MAH含量对HC/LDPE及HC/LDPE-MAH复合材料结构和性能的影响。结果表明：当HC加入量为5wt%时,HC/LDPE复合材料拉伸强度达到最大值15.824 MPa;LDPE-g-MAH的加入可明显改善界面粘结性,提高材料力学性能及热稳定性,当HC含量为20wt%,LDPE-g-MAH含量为4wt%时,HC/LDPE-MAH复合材料的拉伸性能最优。     

硫酸钙晶须增强低密度聚乙烯复合材料的制备及性能研究

制备了硫酸钙晶须(CSW)增强低密度聚乙烯(LDPE)(LDPE/CSW)复合材料,考察了CSW用量对复合体系的界面结构、抗拉性能、熔融和结晶特性以及热分解行为的影响规律。结果表明,CSW在LDPE基体中分散均匀且界面结合良好,提高了抗拉强度和弹性模量,但降低了断裂伸长率和拉伸韧度,在CSW用量为15%(wt,质量分数)制得的LDPE/CSW复合材料的抗拉强度为13.18MPa,弹性模量为158.98MPa,断裂伸长率为167.53%,拉伸韧度为20.02MJ/m~3;CSW的存在对LDPE相的熔融和结晶温度影响甚微,但使LDPE/CSW复合材料的结晶度降低和热稳定性得到提高。     

镁铝复配无卤阻燃剂对EVA/LDPE性能影响研究

以氢氧化镁(MH)和氢氧化铝(ATH)为无卤基材,结合硼酸锌、红磷和硅酮复配制备无卤阻燃剂。将阻燃剂进行改性后与EVA/LDPE共混制备新型无卤阻燃材料。通过正交试验法,研究不同配方无卤阻燃剂对材料的拉伸性能和阻燃性能的影响,进而获得最佳的复配阻燃剂配方。结果表明,在ATH和MH总量为60份的情况下,当MH∶ATH为5∶1,硼酸锌加入量20份,红磷加入量4份,硅酮用量为3份时,复配后无卤阻燃剂对EVA/LDPE的阻燃性能满足垂直燃烧等级UL-94V-0级,机械性能也较好。     

界面相容剂对PE-HD/木粉复合材料力学性能的影响

用不同的界面相容剂对高密度聚乙烯(PE-HD)/木粉复合材料进行界面处理,研究了界面相容剂的含量、种类对复合体系力学性能的影响.结果表明,界面相容剂的加入使复合体系的力学性能有不同程度的改善,其中MAPE的加入,对体系的拉伸、弯曲强度提高最大,在MAPE含量为10%时,复合体系的力学性能达到最大值;经EPDM-MA处理的复合材料,其冲击韧性有明显提高;EVA-MA的加入,使复合材料的性能有所提高;SBS对体系界面粘接力的影响不明显;但MAPE和弹性体SBS复配处理的复合体系,其冲击强度的提高尤为显著,这可能是由于MAPE和SBS在复合体系中发生了协效作用,形成具有柔韧性的中间相所致.     

聚丙烯/镁盐晶须复合材料的形态结构与性能研究

采用哈克单螺杆挤出机制备了聚丙烯/镁盐晶须复合材料,着重研究了增容剂聚丙烯接枝马来酸酐(PP-g-MAH)对复合材料的晶体结构与球晶形态、结晶和熔融行为、热稳定性以及力学性能的影响。研究表明镁盐晶须具有明显的诱导β-晶型的异相成核作用,使聚丙烯结晶温度大幅度提高,球晶尺寸细化。增容剂的加入改善了树脂与晶须的界面性能,界面粘结作用明显增强,提高了拉伸强度和冲击性能,并进一步提高了结晶温度和晶须的成核能力,但降低了β-晶型的含量,不利于β-晶型的生成。     

MAH/GMA共接枝聚乳酸对木粉/PLA复合材料性能的影响

采用熔融接枝法分别制备马来酸酐接枝聚乳酸、甲基丙烯酸缩水甘油酯接枝聚乳酸和马来酸酐/甲基丙烯酸缩水甘油酯共接枝聚乳酸,并利用红外光谱对接枝共聚物进行结构表征。分别以三种接枝共聚物为相容剂,采用注塑成型制备了木粉/PLA复合材料。利用扫描电子显微镜(SEM)对复合材料的断面形貌进行微观分析,结果表明,加入不同接枝共聚物后木粉/PLA复合材料两相看不出明显相界面,界面相容性得到改善。对不同接枝共聚物制备的复合材料的力学性能、加工流动性能和动态流变性能测定的结果显示,加入MAH/GMA共接枝聚乳酸后的木粉/PLA复合材料和未添加相容剂的复合材料相比,拉伸强度和冲击强度分别提高了9.54%和7.23%,复合体系的平衡扭矩和剪切热提高,储能模量及复数黏度均增大。     

植物纤维增强LDPE复合材料的性能研究

以纸纤维和低密度聚乙烯（LDPE）为原料,经配方改性后,利用双螺杆挤出机共混挤出造粒,最后注塑成型复合材料试样。研究了纸纤维的用量、相容剂LDPE-g-MAH的用量及发泡剂AC的用量对该复合材料力学性能的影响。结果表明：纸纤维添加质量分数为40%～50%时,复合材料的拉伸性能最佳,弯曲强度较好;LDPE-g-MAH的加入提高了复合材料的力学性能,且当LDPE-g-MAH添加质量分数为5%时,复合材料的综合性能较好;发泡后复合材料的密度下降,但冲击强度、拉伸强度、弯曲强度都有不同程度的提高,当AC添加质量分数为3%时,复合材料的综合性能较佳。     

β成核剂和镁盐晶须复合改性聚丙烯研究

研究了β成核剂和镁盐晶须对聚丙烯力学性能的影响 ,并对其进行了DSC分析。研究表明 ,镁盐晶须能大大提高聚丙烯的拉伸强度、弯曲强度和弯曲模量 ,而冲击强度基本保持不变。在聚丙烯 /镁盐晶须体系中加入β成核剂后 ,能大大提高复合材料的冲击强度 ,β成核剂在晶须填充聚丙烯体系中有明显的β球晶诱导作用。     

硅油对EVA/ATH复合材料的协同阻燃作用

采用氧指数、锥形量热仪等手段,研究了羟基硅油（HSO）在乙烯-醋酸乙烯酯（EVA）/氢氧化铝（ATH）体系中的协效阻燃作用。氧指数结果表明,随着HSO添加量的增加,复合材料的氧指数略有所下降,样品EVA1～EVA5的氧指数从31下降至27.5。锥形量热仪结果表明,随着HSO添加量的增加,复合材料的热释放速率峰值呈明显的...     

Effect of Amino alcohol functionalized polyethylene as compatibilizer for LDPE/EVA/clay/flame-retardant nanocomposites

The synergistic effect of organo-modified montmorillonite (Nanomer I28E and Cloisite 20A) and metal hydroxides (magnesium hydroxide MH and alumina trihydrate ATH) as flame retardants in LDPE/EVA nanocomposites compatibilized with amino alcohol grafted polyethylene (PEgDMAE) was studied. Morphological characterization of nanocomposites was carried out by means of X-ray diffraction (XRD) and scanning transmission electron microscopy (STEM). Flame-retardant properties of nanocomposites were evaluated by the UL-94 horizontal burning and cone calorimeter tests and limiting oxygen index (LOI). Thermal degradation behavior was analyzed with a Fourier transform infrared coupled with the thermogravimetric analyzer (TG-FTIR). The XRD analysis showed a displacement of the d₀₀₁ plane characteristic peak of clay to lower angles, which indicates an intercalated–exfoliated morphology. From STEM images it was observed a good dispersion of flame retardants (MH and ATH) throughout the polymer matrix which was reflected in flame-retardant properties. TG-FTIR showed a better thermal stability of nanocomposites and the gases evolved during combustion showed an important reduction. Based on thermal stability and thermal degradation results, the flame-retardant mechanism of LDPE/PEgDMAE/EVA/Clay/MH nanocomposites was proposed.     

Aluminum hydroxide filled ethylene vinyl acetate (EVA) composites: effect of the interfacial compatibilizer and the particle size

Ethylene vinyl acetate (EVA) copolymer was filled with aluminum hydroxide (ATH) with three different sizes of 1.8, 1.2 and 0.8 μm in various volume fractions. The effect of interfacial compatibilizer on the properties of the composites was studied by morphology observation, dynamic mechanical analysis, tensile and flame tests. The results illustrated that the incorporation of functionalized polyethylene combined with dicumyl peroxide (DCP) and the silane coupling agent led to a pronounced improvement in the tensile strength compared to the composites with ATH untreated or treated by silane coupling agent alone. It was found that good dispersion and interfacial adhesion between the ATH particles and the matrix can improve the flame properties of composites. The particle size has a great effect on the flammability of the EVA/ATH composites. ATH with smaller particle size can increase the LOI value and improve the UL-94 flammability of the composites.     

Dispersion and roles of montmorillonite on structural,flammability, thermal and mechanical behaviours of electron beam irradiated flame retarded nanocomposite

In this work, the effects of montmorillonite (MMT) dispersion and electron beam irradiation on intercalation and flammability-thermal behaviours of alumina trihydrate (ATH) added low density polyethylene and ethylene vinyl acetate (LDPE–EVA) blends were investigated. MMT and ATH added LDPE–EVA blends were compounded using Brabender mixer and compression moulded into sheets. The samples sheets were electron beam irradiated in the dosage range of 0 to 250 kGy. The dispersion and intercalation of nano-MMT in LDPE–EVA matrix were investigated through X-ray diffraction (XRD) analysis. The d-spacing measurements revealed that the addition of nano-MMT has effectively intercalated into polymer matrix and this has enhanced the compatibility of ATH particles and LDPE–EVA matrix. Limiting oxygen index test (LOI) revealed that the incorporation of MMT into ATH added LDPE–EVA blends as improved the flame retardancy up to 26.5 LOI%. Besides, the application of electron beam irradiation were also improved the flame retardancy of the blends by increasing the LOI% for about 2% compared to non-irradiated samples. The application of irradiation dosage up to 250 kGy has rapidly improved the thermal stability of blends by delaying decomposition temperature and also promoting formation of char. The increasing of MMT loading level and irradiation dosage has effectively enhanced tensile strength and Young’s modulus by intercalating polymer matrix into interlayer galleries of MMT particles. Beside, the formation of crosslinking networks in polymer matrix also could further enhance the tensile strength and Young’s modulus. The intercalation effect of MMT particles and formation of crosslinking networks in polymer matrix could improve the thermal and mechanical properties. Consequently, this study has demonstrated that addition of MMT and electron beam irradiation into ATH added LDPE–EVA blends could produce better flammability, thermal and physical properties of ATH added LDPE–EVA blends.     

Effect of aluminium hydroxide,chlorinated polyethylene,decabromo biphenyl oxide and expanded graphite on thermal,mechanical and sorption properties of oil-extended ethylene–propylene–diene terpolymer rubber

Oil-extended EPDM composites with different flame retardant fillers like aluminium hydroxide (ATH), chlorinated polyethylene (CPE), decabromobiphenyl oxide (DBBO) and expanded graphite (EG) were prepared by conventional mill mixing. Thermal, mechanical and sorption characteristics of the vulcanizates were studied. The effect of different fillers on the flammability of the composites was measured using Limiting Oxygen Index (LOI) and UL-94 HB tests. Scanning Electron Microscopic (SEM) studies of the composites were also conducted. ATH and CPE improve the thermal stability of the composite substantially. Among the four fillers ATH has the highest reinforcing effect on the EPDM rubber. Sorption studies of the composite showed that ATH reduced the swelling rate of the microcomposite considerably. All the four fillers were effective in improving the flame retardant property. Filler dispersion studies and SEM images point to a uniform dispersion of filler in the matrix which is in good agreement with significant improvement in mechanical properties.     

Electron beam irradiated HDPE/EVA/Mg(OH) composites for flame-retardant electric cables

The mechanical properties and flammability of high-density polyethylene (HDPE)/ethylene vinyl acetate (EVA) mixed with various amounts of magnesium hydroxide (Mg(OH)₂) as the filler in composites, irradiated with electron beam at an irradiation dose of 150 kGy, have been studied. It is found that high-energy electron beam irradiation has significant effects on the mechanical properties of the HDPE/EVA/Mg(OH)₂ composites. The tensile strength and elastic modulus increased greater than in the unirradiated ones. Meanwhile, with increasing the content of Mg(OH)₂ in the composites, the limiting oxygen index (LOI) value increased sharply. The microstructure of the caves of the unirradiated HDPE/EVA/Mg(OH)₂ composites show poor interface of composites compared with the irradiated ones, as observed in SEM micrographs.     

Electron beam irradiated HDPE/EVA/Mg(OH)2 composites for flame-retardant electric cables

The mechanical properties and flammability of high-density polyethylene (HDPE)/ethylene vinyl acetate (EVA) mixed with various amounts of magnesium hydroxide (Mg(OH)₂) as the filler in composites, irradiated with electron beam at an irradiation dose of 150 kGy, have been studied. It is found that high-energy electron beam irradiation has significant effects on the mechanical properties of the HDPE/EVA/Mg(OH)₂ composites. The tensile strength and elastic modulus increased greater than in the unirradiated ones. Meanwhile, with increasing the content of Mg(OH)₂ in the composites, the limiting oxygen index (LOI) value increased sharply. The microstructure of the caves of the unirradiated HDPE/EVA/Mg(OH)₂ composites show poor interface of composites compared with the irradiated ones, as observed in SEM micrographs.     

微胶囊化膨胀型阻燃剂与有机蒙脱土协效阻燃乙烯-醋酸乙烯共聚物性能

通过纳米复合的方式,将微胶囊化的膨胀型阻燃体系—聚磷酸铵(APP)-季戊四醇(PER)与有机改性的片层蒙脱土(OMMT)用于协效阻燃乙烯-醋酸乙烯共聚物(EVA)。采用XRD、TEM、TGA、极限氧指数(LOI)、垂直燃烧(UL-94)、锥形量热仪、烟密度和动态机械热分析对微胶囊化APP(MCAPP)-微胶囊化PER(MCPER)-OMMT/EVA复合材料的结构与性能进行研究。研究结果表明,OMMT被完全剥离开,并以层离或插层的状态分散在EVA中;MCAPP-MCPER与OMMT之间存在明显的协效阻燃作用,用3wt%OMMT代替MCAPP-MCPER后,MCAPP-MCPER-OMMT/EVA复合材料的LOI值从25.5vol%提高到29.5vol%,垂直燃烧结果由V-2上升到V-0级别,残炭量也由14.5wt%增大到15.9wt%,烟密度由154.7 g/s降低到97.5 g/s,材料的阻燃性能得到有效提高。此外,万能拉伸测试及动态机械热分析测试表明,通过纳米复合制备的阻燃MCAPP-MCPER-OMMT/EVA复合材料具有更好的力学和动态热机械性能。      

LDPE/EVA/MWCNTs/CF复合材料的电学及流变性能

用熔融共混法制备了低密度聚乙烯(LDPE)/乙烯-醋酸乙烯共聚物(EVA)/多壁碳纳米管(MWCNTs)/碳纤维(CF)复合材料。使用高阻计、扫描电子显微镜、旋转流变仪等研究了导电填料及基体组成对材料的电性能和流变性能的影响。发现MWCNTs与CF共同作为导电填料具有协效作用,使得材料其不仅具有渗滤阈值低的特点,并且当填料含量超过阈值时,材料的导电性能相比于纯MWCNTs填充的复合材料电阻率降低了2个数量级。流变测试发现MWCNTS相比于CF对基体分子链运动的限制更为明显,MWCNTs含量的增多会增加材料的黏度并使材料从"类液"的粘弹行为转变为"类固"的粘弹行为。     

Surfactant effects on poly(ethylene-co-vinyl acetate)/cellulose composites

Cellulose whiskers, isolated from banana waste fibres, were used as a reinforcement in poly(ethylene-co-vinyl acetate) [EVA] matrices, to develop composites. A non-ionic surfactant, poly(ethylene glycol ether), was used to improve the dispersion characteristics of the cellulose whiskers in EVA/cellulose whisker composites. The influence of the surfactant on the morphology, the mechanical properties and the thermal characteristics of the resultant EVA/cellulose whisker composites has been examined. Theoretical models, namely the Halpin–Tsai model and the Nicolais–Narkis model have been used to provide a basis for comparing the results those were derived from investigations of the tensile properties of the composites.