改性LDPE高发泡弹性材料的研究

以低密度聚乙烯（LDPE）为基体原料,乙烯-辛烯共聚物（POE）为增韧材料,CaCO3为填充料,硼酸酯为改性剂,添加AC发泡剂、DCP交联剂等助剂;采用界面改性、密炼塑化、模压发泡方法制备改性LDPE高发泡弹性材料,并对其性能进行分析研究。结果表明：含LDPE70质量份、POE30质量份、改性CaCO310质量份、AC2质量份、DCP1.4质量份的发泡材料,其拉伸强度2.40MPa、撕裂强度5.82KN/m、断裂伸长率163.2%、密度0.236g/cm3、收缩率1.1%,物理力学性能优良。     

LDPE/nano-CaCO_3复合发泡材料的制备工艺与性能研究

采用模压发泡法制备了低密度聚乙烯/纳米碳酸钙(LDPE/nano-CaCO3)复合发泡材料。研究不同含量的nano-CaCO3、发泡剂AC、交联剂DCP等对LDPE/nano-CaCO3力学性能及发泡效果的影响,确定了最佳工艺路线。结果表明:随着nano-CaCO3用量的增加,LDPE/nano-CaCO3复合发泡材料拉伸强度和表观密度逐渐增大,发泡倍率逐渐减小。当nano-CaCO3用量为30%,AC用量为9%～11%,DCP用量为0.08%时,发泡材料的综合性能最佳。热重分析表明:加入nano-CaCO3后,LDPE发泡材料的热稳定性得到提高。     

陶土的表面改性及其增强EPM发泡材料的研究

以陶土为补强填充剂,稀土铝酸酯、油酸酰胺、硬脂酸单甘油酯为改性剂,二元乙丙橡胶（EPM）为基本原料,经界面改性、密炼塑化、模压发泡方法制备EPM发泡材料。采用吸水性测定法、亲油化度测定法、红外光谱法分析陶土的表面改性效果;用扫描电镜观察陶土在EPM材料中的分散均匀性以及对EPM发泡材料泡孔的影响;检测了EPM发泡材料的物理力学性能。结果表明：稀土铝酸酯改性陶土效果最好,含20%改性陶土的EPM发泡材料,其孔径均匀性较好,拉伸强度提高66.3%,撕裂强度提高了27.8%,收缩率降低了1.6%,物理力学性能优良。     

POE/LDPE复合体系弹性发泡材料制备

采用过氧化二异丙苯(DCP)化学交联方法,研究了发泡剂偶氮二甲酰胺(AC)、DCP加入量以及POE/LDPE(乙烯辛烯共聚物/低密度聚乙烯)质量比对POE/LDPE复合体系弹性发泡材料性能的影响。结果表明,当POE/LDPE质量比为3/7,AC和DCP添加量分别是树脂总质量的1%和2%时,发泡材料吸水率、表观密度、拉伸强度、凝胶率和邵氏硬度分别为4.2%,0.062 7g/cm3,1.20 MPa,78.5%和17,制得的材料综合性能最佳,泡孔均匀细密。     

PP／LDPE模压发泡工艺的研究

采用低密度聚乙烯（LDPE）对聚丙烯（PP）进行共混改性,以过氧化二异丙苯（DCP）为交联剂,偶氮二甲酰胺（AC）为发泡剂,通过模压法制备了聚丙烯发泡材料。研究了LDPE,AC,DCP的用量以及模压工艺条件对聚丙烯发泡效果的影响。结果表明：当m（PP）：m（LDPE）：77z（AC）：m（DCP）=50：50：4：0．1,模压温度200℃时,聚丙烯发泡材料的密度最小,为0．13g／cm^3。     

LDPE/EVA鞋底发泡材料的研究

讨论了发泡剂偶氮二甲酰胺(AC)、橡胶(EPDM、NBR)、填料超细碳酸钙(CaCO3)用量对LDPE／EVA发泡材料性能的影响，研制出发泡材料密度及力学性能满足运动鞋中底要求的配方。结果表明：AC用量为6份时，发泡材料密度达到0．078g／cm^3；EPDM有效改善了发泡材料的强度，当EPDM加入15份时，发泡材料密度和力学性能优异；超细CaCO3可以提高LDPE／EVA／NBR发泡材料的强度，当超细CaCO3用量为30份时，发泡材料性能较好。     

ABS微孔发泡材料的制备与性能研究

利用化学交联模压法制备了丙烯腈–丁二烯–苯乙烯塑料(ABS)微孔发泡材料,研究了发泡剂偶氮二甲酰胺(AC)、活化剂氧化锌(ZnO)、交联剂过氧化二异丙苯(DCP)用量对ABS微孔发泡材料力学性能和泡孔结构形态的影响。结果表明,当AC为2份、DCP为0.15份、ZnO为0.2份时,制得的ABS微孔发泡材料的泡孔密度为1.31×108cells/cm3,平均泡孔尺寸为24μm,比强度达到44.7 N/tex,综合性能最佳,可以满足微孔发泡材料的要求。     

LDPE/EPDM共混料发泡工艺探讨 Ⅰ.发泡剂AC、交联剂DCP对发泡工艺的影响

重点讨论了发泡剂AC、交联剂DCP对低密度聚乙烯/三元乙丙橡胶(LDPE/EPDM)发泡工艺的影响。探讨了在发泡过程中AC、DCP分解曲线变化,泡体凝胶率、密度的变化与AC及DCP用量之间的关系。     

LDPE/EVA发泡材料的研制

以偶氮二甲酰胺(AC)为发泡剂，过氧化二异丙苯(DCP)为交联剂，硬脂酸锌(ZnSt)为活化剂，二氧化硅(SiO₂)为匀泡剂，低密度聚乙烯(LDPE)和乙烯-醋酸乙烯酯共聚物(EVA)为发泡塑料载体，研究了发泡材料的最佳原料配比和加工条件，并对发泡材料的各项性能进行了表征。实验发现当PE为70 phr、EVA为13 phr、DCP为2 phr、AC为15 phr时得到的发泡试样综合性能最好。     

炭黑填充LDPE/EVA体系发泡复合材料的电阻-温度特性

以低密度聚乙烯(LDPE)和乙烯-乙酸乙烯酯(EVA)为主基体,乙炔炭黑(ACET)为导电填料,偶氮二甲酰胺(AC)为发泡剂,过氧化二异丙苯(DCP)为交联剂制备了LDPE/EVA/CB导电泡沫复合材料.研究了此复合材料的泡孔结构、渗流阀值、阻温特性.并分析了不同炭黑填充量、不同LDPE/EVA配比、相同基体配比发泡与否对复合材料阻温性能的影响.制备的导电泡沫具有比较理想的泡孔结构.经过升温电阻测试,发现LDPE/EVA/ACET导电发泡复合材料具有良好的开关特性,呈现明显的PTC特性.确定了LDPE/EVA的合理配比及ACET、AC、DCP的适宜用量,从而获得了既具有优良的泡沫性能,又有良好PTC特性的导电泡沫材料.     

Enhancement of processability and foamability of ground tire rubber powder and LDPE blends through solid state shear milling

The foamed composites made from low-density polyethylene(LDPE) and ground tire rubber(GTR) powder using azodicarbonamide as chemical blowing agent have been investigated. Solid state shear milling was used to enhance the processability and foamability of LDPE/GTR blends by a pan-mill type mechanochemical reactor. First the blends of LDPE/GTR were prepared by co-milling, then the samples were melt-mixed in a Brabender Plasti-Corder, saturated with blowing agent, crosslinking agent and blowing co-agent, and finally the saturated specimens were expanded during the pressure-quench process. The results indicated that the mechanical properties of the LDPE/GRT foamed composites were improved, and the blends of co-milled GTR and LDPE powder showing better processability and foamability than those obtained in a conventional melt-mixing manner, as indicated by the rheological and morphological studies.     

EVA改性聚乙烯无卤阻燃泡沫塑料的研究

以乙烯－醋酸乙烯酯（EVA）改性低密度聚乙烯（LDPE）,添加无卤阻燃剂氢氧化镁,采用高温混炼,化学交联,模压一步法来制备无卤阻燃改性PE泡沫,通过力学性能,扫描电镜,差示扫描量热法（DSC）3种测试方法,重点探讨了无卤阻燃剂Mg(OH)2对材料性能的影响以及EVA改性剂,协同阻燃剂三氧化二锑（Sb2O3),交联剂过氧化二异丙苯（DCP）,发泡剂偶氨二甲基酰胺（AC）,发泡剂N,N′－二亚硝基戊次甲基四胺（H）,填料等因素对无卤阻燃改性PE泡沫塑料性能的影响。实验结果表明：选择LDPE70份,醋酸乙烯（VA）质量分数33％的EVA30份,Mg(OH)2140份,AC4份,H4份,DCP0．8份,三盐基硫酸铅（3PbO)1份,二盐基亚磷酸铅（2PbO)1份,复合盐1份,硬脂酸（SA）1份,硬脂酸钡（BaSt)2份可制得阻燃性能,力学性能和加工性能较好的改性PE泡沫塑料。     

可膨胀微球在聚乙烯中的发泡特性研究

探讨了可膨胀微球发泡剂(Expancel)在低密度聚乙烯(LDPE)体系中的发泡规律。表征了Expancel的形态特征和热性能;然后将Expancel混入LDPE中,探讨了发泡温度、交联程度、发泡剂用量等工艺和配方因素对LDPE发泡的影响。结果表明:Expancel微球膨胀后的体积是膨胀前的50倍,10 phr用量可使LDPE发泡体密度达0.2g/cm3,实测密度与理论计算值相当;在Expancel最高膨胀温度之下很宽的温度范围内,温度对LDPE发泡倍率的影响不大;LDPE的轻度交联有利于Expancel的膨胀稳定性。     

LDPE/EPM/炭黑导电复合材料的研究

制备了低密度聚乙烯(LDPE)／二元乙丙橡胶(EPM)／炭黑导电复合材料。用带功能基团的表面改性剂对炭黑进行表面处理,在炭黑低填充量下即获得了导电率高、综合性能优良的导电复合材料。研究了基体树脂的结构、工艺方法、炭黑的预处理、复合材料的后处理(退火)等对LDPE／EPW炭黑导电复合材料导电性能的影响。     

Mechanical properties of foams comprising virgin and waste polyethylene

Summary This paper addresses the use of waste polyethylene (p-PE) in low-density polyethylene (LDPE) foams with azodicarbonamide as the blowing agent. The amount of blowing agent was fixed at 5% for all mixtures, with 0.5% cross-linking agent, 1.7% zinc oxide and 1.7% stearic acid, by weight. Proportions of LDPE/p-PE (% wt) tested in foams were: 100/0, 85/15, 70/30, 60/40, 50/50 and 30/70. The components used to obtain the foams were processed in a Banbury mixer at 120 °C. The pre-form (non expanded material) was placed in a mold and the foaming was carried out in a hot press at 190 °C. The apparent densities of the foams obtained were 60–65 kg.m^-3. The mechanical properties (compression set under constant deflection, compressive strength and tear resistance) of LDPE foams containing different proportions of p-PE were compared with the LDPE foam obtained from virgin material only. The mechanical properties of foams with p-PE in their formulation were superior in relation to foams made from LDPE, because p-PE contains high-density polyethylene (HDPE), which is more rigid than LDPE.     

Effect of the molecular structure of ethene–propene and styrene–butadiene copolymers on their compatibilization efficiency in low‐density polyethylene/polystyrene blends

The effect of the molecular structure of styrene–butadiene (SB) block copolymers and ethene–propene (EPM) random copolymers on the morphology and tensile impact strength of low‐density polyethylene (LDPE)/polystyrene (PS) (75/25) blends has been studied. The molecular characteristics of SB block copolymers markedly influence their distribution in LDPE/PS blends. In all cases, an SB copolymer is present not only at the interface but also in the bulk phases; this depends on its molecular structure. In blends compatibilized with diblock copolymers, compartmentalized PS particles can also be observed. The highest toughness values have been achieved for blends compatibilized with triblock SB copolymers. A study of the compatibilization efficiency of SB copolymers with the same number of blocks has shown that copolymers with shorter PS blocks are more efficient. A comparison of the obtained results with previous results indicates that the compatibilization efficiency of a copolymer strongly depends both on the blend composition and on the properties of the components. The compatibilization efficiency of an EPM/SB mixture is markedly affected by the rheological properties of the copolymers. The addition of an EPM/SB mixture containing EPM with a higher viscosity leads to a higher improvement or at least the same improvement in the tensile impact strength of a compatibilized blend as the same amount of neat SB. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

LDPE／EVA／CPE并用微孔鞋底料的研制

采用模压法研究了化学交联LPDE/EVA/CPE并用微孔鞋底料的制造方法,着重讨论了LDPE/EVA/CPE并用比,不同种类的橡胶改性剂以及发泡剂、交联剂、填充剂用量对微孔鞋底物理机械性能的影响。实验结果表明,采用国产原料CPE,当LDPE:EVA:CPE=50:30:20时,并配以超细碳酸钙20份和其他助剂,可制得性能较好的微孔鞋底材料。     

Preparation of low‐density polyethylene foams with high rebound resilience by blending with polyethylene–octylene elastomer

Low‐density polyethylene (LDPE)/polyethylene–octylene elastomer (POE) foams with different composition ratios (POE, cross‐linking agent, and blowing agent) were produced by using the continuous cross‐linking and foaming process to improve the rebound resilience of chemical cross‐linked LDPE foams. The effects of POE, cross‐linking agent, and foaming agent on rebound resilience of LDPE/POE foams were investigated by using a rebound test, cross‐linking degree experiment, differential scanning calorimetry, and scanning electron microscopy. Results show that the rebound resilience of LDPE was improved by increasing the flexibility of cell walls and the cell density and decreasing the foam density. Compared with the rebound resilience of pure LDPE (33%), the proposed LDPE/POE foams could meet the requirements of gymnastics mats for high rebound resilience (55%). POLYM. ENG. SCI., 53:2527–2534, 2013. © 2013 Society of Plastics Engineers     

木质素填充LDPE、EVA对复合物性能的影响

以木质素为填充剂分别与低密度聚乙烯(LDPE)、乙烯-乙酸乙烯酯共聚物(EVA)共混,经双螺杆造粒机共混挤出造粒,再经吹塑成膜。研究了木质素/LDPE、木质素/EVA共混物薄膜的表面形貌、力学性能、热性能和红外光谱。热分析表明木质素与EVA共混物的热稳定性比木质素与LDPE的共混物热稳定性好;红外光谱分析表明木质素与EVA分子间产生了强烈的相互作用,扫描电镜分析表明木质素与EVA共混的相容性较好,力学性能分析表明低于30%的木质素与LDPE、EVA共混力学性能较好。     

Melt strength and film bubble instability of LLDPE/LDPE blends

The relevance of measuring the melt strength of low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and their blends to their performance in terms of bubble stability in the film blowing process has been investigated. A good correlation between the melt strength values for two series of LLDPE/LDPE blends and the size of the operating window for stable film bubble formation has been established. Both the macromolecular structure of the parent polymers, and melt morphology play an important role in the performance of these blends in the film blowing process. © 1999 Society of Chemical Industry