硅烷接枝交联LDPE、LLDPE及其共混物的结构研究

利用红外光谱、凝胶渗透色谱、热延伸试验、差示扫描量热法、扫描电子显微镜等方法研究了低密度聚乙烯（LDPE）、线型低密度聚乙烯（LLDPE）及其共混物的乙烯基硅烷接枝及交联产物的分子结构、熔融行为和形态。结果表明：硅烷接枝后，LDPE、LLDPE的重均摩尔质量小幅增加；硅烷接枝交联能力为：LLDPE〉LDPE／LLDPE共混物〉LDPE；接枝和交联使LDPE、LLDPE及其共混物的结晶度降低，晶粒变得不均匀；硅烷接枝和交联能增加LDPE／LLDPE共混物的相容性；交联结构提高了LDPE、LLDPE及其共混物的抗冲性。     

硅烷接枝交联HDPE／LLDPE共混物性能研究

采用引发剂过氧化二异丙苯（DCP）、硅烷偶联剂乙烯基三乙氧基硅烷（VTEOS）和催化剂二月桂酸二丁基锡（DBTL）,通过双螺杆挤出机对高密度聚乙烯（HDPE）和线性低密度聚乙烯（LLDPE）的共混物进行硅烷接枝交联反应。通过力学测试和DSC研究产物不同凝胶含量对其性能影响。研究表明硅烷交联聚乙烯的拉伸和冲击强度随交联度的增大而提高,但产物结晶度和熔点有所下降,同时结晶均匀性变差。     

聚乙烯反应挤出接枝马来酸酐的研究

以过氧化二异丙苯(DCP)为引发剂,使用反应挤出机研究了不同种类聚乙烯及其共混物接枝马来酸酐的反应规律。实验结果表明:产物的接枝率和熔体流动速率(MFR)变化与聚乙烯的种类有直接关系,接枝性能从优到差的顺序为:LDPE>LLDPE>HDPE;引发剂DCP对LDPE接枝产物的MFR影响显著,对LLDPE次之,对HDPE的MFR几乎没有影响;聚乙烯共混物的接枝性能取决于组成共混物的聚乙烯种类和用量。接枝产物及纯化后样品的红外光谱分析表明,酐基是以化学键连接到聚乙烯分子链上,接枝产物几乎不含游离态的马来酸酐。     

国产DFDA7042型LLDPE在滚塑成型中的应用

报道了以国产原料为基础、对薄膜级线型低密度聚乙烯(LLDPE)在滚塑成型中的应用进行的研究,通过与高密度聚乙烯(HDPE)共混。提高了LLDPE的综合性能。探讨了共混比对共混物力学性能及流动性的影响,并经老化试验证明,该共混材料可以替代滚塑级LLDPE。     

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.     

高密度聚乙烯和线性低密度聚乙烯共混用于包装薄膜的生产

研讨了线性低密度聚乙烯(LLDPE)/高密度聚乙烯(HDPE)共混取代线性低密度聚乙烯(LLDPE)/低密度聚乙烯(LDPE)共混用于包装薄膜的生产,并测试了其物理性能。     

HDPE/LDPE复合交联物的热降解研究

采用热重分析仪（TG）考察了高密度聚乙烯（HDPE）／低密度聚乙烯（LDPE）复合交联物的热稳定性。结果显示，HDPE／LDPE复合交联物的热稳定性低于HDPE／LDPE共混物。FTIR分析证实，交联反应使聚乙烯（PE）的支化程度提高，取代基的位阻效应在一定程度上影响了PE的热降解过程。在N2气氛下，HDPE／LDPE共混物及交联物的热降解过程均为一步降解反应。Kissinger法求解HDPE／LDPE共混物及其复合交联物的热降解活化能发现，LDPE质量分数在20％～30％之间变化时，HDPE／LDPE交联物的热降解过程对温度的敏感性发生了突变。     

铝塑复合管用接枝型聚乙烯类热熔胶的制备及性能研究

以高密度聚乙烯(HDPE)和线型低密度聚乙烯(LLDPE)为主体树脂,过氧化二异丙苯(DCP)为引发剂,顺丁烯二酸酐(MAH)为主要单体进行接枝反应挤出制取PE-g-MAH接枝物;然后将该接枝物、增黏剂及其它助剂等进行共混挤出,制备出粘接强度高、流动性能好的铝塑复合管用热熔胶。讨论了原料配比、接枝单体、DCP、增黏树脂和乙烯类弹性体等对该热熔胶性能的影响,并采用红外光谱(FT-IR)技术对该接枝物的结构进行了表征。结果表明:以m(HDPE)∶m(LLDPE)=1∶5,适量控制DCP和不饱和单体的用量,并采用MAH/AA混合单体进行接枝改性,在保证热熔胶流动性能较好的前提下,可得到接枝率及剥离强度均较高的热熔胶;另外,加入适量的乙烯类弹性体,热熔胶的剥离强度明显提高。     

BHDPE/HDPE/LLDPE共混体系的研究

采用线性低密度聚乙烯(LLDPE)对双峰高密度聚乙烯(BHDPE)和高密度聚乙烯(HDPE)进行共混,测定共混物的力学性能和DSC曲线。结果显示共混物均可以产生共晶,LLDPE对BHDPE力学性能影响较大;在LLDPE/HDPE中添加BHDPE,三者共混物具有更好的力学性能,流变性能显示三者共混物体系黏度变化不大,为制备性能最优、成本最低的三者共混物提供了依据。     

硅烷接枝HDPE和LLDPE的反应动力学研究

用差示扫描量热法研究了过氧化二异丙苯引发的硅烷接枝高密度聚乙烯(HDPE)、线型低密度聚乙烯(LLDPE)反应及其动力学特性。结果表明,该反应可按假定的自由基反应机理,用简化的动力学模型描述,遵循一级反应动力学,得出HDPE、LLDPE的接枝反应活化能分别为(190±5)kJ/mol、(160±5)kJ/mol,LLDPE的接枝反应热和反应程度大于HDPE。     

Silane grafting reactions of LDPE,HDPE, and LLDPE

Vinyl trimethoxysilane and vinyl triethoxysilane grafting reactions, induced by dicumyl peroxide, of LDPE, HDPE, and LLDPE were investigated. The apparent activation energy of vinyl trimethoxysilane grafting reactions was positive when the reactions were induced by 0.2 phr of the peroxide. The apparent activation energies were negative when 0.05, 0.1, 0.15, and 0.25 phr of peroxide were used. The extents of vinyl trimethoxysilane grafting reactions of polyethylenes were in the order of LLDPE > LDPE > HDPE, although the extents of peroxide cross‐linking were in the order of LDPE > LLDPE > HDPE. As compared with vinyl trimethoxysilane, vinyl triethoxysilane produced a relatively high extent of grafting reactions of LDPE but showed a relatively low rate of water cross‐linking reactions of the silane‐grafted LDPE. The investigation of effects of the amount of peroxide on the vinyl trimethoxysilane grafting reaction heats demonstrated that the extent of silane grafting reactions increased proportionally as peroxide was increased until a certain amount (the value was dependent on the amount of silane used). Beyond this amount of peroxide, the silane grafting did not increase, whereas the peroxide cross‐linking appeared to increase significantly with increasing amounts of peroxide. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3404–3411, 1999     

LDPE HDPE LLDPE的硅烷接枝反应

研究了DCP (过氧化异丙苯)为引发剂,A1 71 (乙烯基三甲氧基硅烷)与A1 51 (乙烯基三乙氧基硅烷)在LDPE (低密度聚乙烯) ,HDPE (高密度聚乙烯) ,LLDPE (线性低密度聚乙烯)上的接枝反应。A1 71接枝反应过程中,当过氧化物的加入量为0 .2 %时,活化能为正值。而当加入量为0 . 0 5%、0 . 1 %、0 . 1 5%、0 2 5%时,活化能为负值。尽管过氧化物在PE (聚乙烯)中交联反应程度的顺序为:LDPE >LLDPE >HDPE ,但A1 71接枝反应程度的顺序为LLDPE >LDPE >HDPE。与A1 71相比,A1 51在LDPE上具有较高的接枝反应速率,但它在水交联反应过程中,呈现出相对较低的反应速率。通过研究加入过氧化物量的变化对A1 71接枝反应热的影响,可知在过氧化物未达到一定量前(这个数值取决于所加入的硅烷的量) ,当过氧化物增加时,反应热是随之增加的。     

HDPE/LLDPE/POE薄膜性能的研究

采用线型低密度聚乙烯（LLDPE）和热塑性弹性体乙烯-辛烯共聚物（POE）对高密度聚乙烯（HDPE）薄膜进行改性,研究了LLDPE和POE对共混体系薄膜力学性能、加工性能的影响,探讨了LLDPE增强HDPE的机理。结果表明,加入一定量LLDPE,使HDPE／LLDPE薄膜的拉伸强度较纯HDPE薄膜有所增加,而单位冲击破损质量则有所下降。当w（LLDPE）为15％时,HDPE／LLDPE薄膜的拉伸强度提高21．6％,薄膜的单位冲击破损质量降低23．0％。在HDPE／LLDPE/POE三元体系中,当w（POE）,w（LLDPE）分别为10％,15％时,薄膜的拉伸强度、单位冲击破损质量、断裂伸长率比纯HDPE薄膜分别提高2．3％,113％。36．0％,综合性能良好。     

Compatibility of HDPE/postconsumer HDPE blends using compatibilizing agents

Mechanical properties, molecular weight, X‐ray diffraction, and differential scanning calorimetry (DSC) characterization of blends of virgin high‐density polyethylene (HDPE) with two types of recycled material were investigated. The recycled came from urban plastic waste; one kind was only washed and grounded and the other was extruded and pelletized to remove most of contaminant particles. Starting with the 30/70 virgin/grounded recycled and 50/50 virgin/pelletized recycled blends the recycled content was increased in both blends and compatibilizing agents were used to increase the blend performance. A mixture of phenolic antioxidants and phosphite costabilizers under the name of Recycloblend?, ethylene vinyl acetate (EVA) copolymer, low‐density polyethylene (LDPE), and linear low density polyethylene (LLDPE) were used as compatibilizers. The effect of these additives and the recycled content on the performance of extrusion blow‐molded bottles was determined. The results suggest that blends of virgin/grounded recycled and virgin/pelletized recycled HDPE, in general, were not significantly different among each other and both had a quite similar behavior than the virgin HDPE when compatibilizing agents were used. The addition of compatibilizing agents yielded a material with properties similar to those for the virgin HDPE, helping to reduce the effect of polymers degradation on the rheological and mechanical behavior, with Recycloblend and LLDPE being the most effective for the blends with grounded recycled material, and LLDPE y EVA, for the blends with pelletized recycled. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3696–3706, 2006     

Thermal and mechanical properties of silane‐grafted water crosslinked polyethylene

The effects of linear low density polyethylene (LLDPE) grafting with vinyltrimethoxysilane by different types and contents of peroxide were studied. When grafting silane onto LLDPE, with 0.10 phr of Dicumyl peroxide (DCP) or 0.05 phr content of 2,5‐Dimethyl‐2,5‐di (tert‐butyl‐peroxy)‐hexane (DHBP), it was found that the grafting effect was improved; however, as Di(2‐tert‐butylperoxypropyl ‐(2))‐benzene (DIPP) or excess DHBP was used, LLDPE was supposed to cause self‐crosslinking, which reduced the grafting effect of silane and was invalid in the processing of extrusion. In this study, vinyl trimethoxysilane (VTMS) was grafted onto various polyethylenes (HDPE, LLDPE, and LDPE) using DCP as an initiator in a twin screw extruder. The grafted polyethylenes were able to crosslink utilizing water as the crosslinking agent. The effects of varied crosslinking time on the mechanical properties of the crosslinked polyethylenes were studied. It was found that the HDPE and LLDPE were apt to crosslink during the grafting process and thus decreased the grafting ratio. Multiple melting behavior was observed for crosslinked LDPE and LLDPE. Mechanical and thermal properties of the crosslinked PE are much better than that of uncrosslinked PE. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2383–2391, 2005     

铝塑复合管硅烷交联聚乙烯专用料的研究

研究了高密度聚乙烯（HDPE）／线性低密度聚乙烯（LLDPE）硅烷接枝交联体系。分析了过氧化二异丙苯（DCP），乙烯基三乙氧基硅烷（VTES），加工设备及工艺条件（温度，螺杆转速）对体系熔体流动速率（MFR）和凝胶含量的影响。并用Buss混炼设备制备出高流动性的铝塑复合管硅烷接枝交联PE专用料。     

高密度聚乙烯/低密度聚乙烯复合交联特性

采用转矩流变仪考察了高密度聚乙烯／低密度聚乙烯在有机过氧化物存在下的交联过程，对比了不同原料配比制取的交联物的微观结构形态及熔融结晶特性，同时针对典型交联物采用莫志深法考察了其结晶动力学。结果表明．原料配比、引发剂浓度以及添加二氧化硅对交联物的微观结构和性能具有显著的影响。选择合适的原料配比和交联工艺，可以获得相对完善的网络交联结构。