苯乙烯氯化原位接枝改性氯化聚氯乙烯的研究

采用氯化原位接枝技术在聚氯乙烯（PVC）进行氯化反应的同时接枝上各种不同单体．从而制备改性的氯化聚氯乙烯（CPVC）。研究了PVC固相法氯化原位接枝St的规律，讨论了单体苯乙烯（St）加入量、氯含量对产物物理力学性能及流变性能的影响。结果表明：St的加入量为10份时，改性CPVC的屈服强度明显高于空白CPVC的屈服强度，但维卡软化点降低；改性CPVC的屈服强度和维卡软化点均随氟含量增加而增大；St的加入量适当，可以同时提高改性CPVC的屈服强度和冲击性能，降低熔体粘度。     

硅烷接枝交联法制备发泡用高熔体粘度聚丙烯

以过氧化物为引发剂,不饱和硅烷为接枝单体,不饱和烃类为接枝助剂,并加入交联催化剂,通过反应型双螺杆挤出机一步实现共聚型聚丙烯的接枝和交联;制备出了可用于发泡的高熔体粘度聚丙烯。通过熔体质量流动速率(MFR)和凝胶含量的变化,研究试剂体系对接枝交联改性的作用。结果显示,改性后PP的MFR可降低至0．1 g／ 10min以下,凝胶含量可高达48％以上,体系中各组分都显著影响改性材料熔体的流动性和凝胶含量,缺一不可。随引发剂和硅烷单体含量的增加,体系熔体流动性逐渐降低,凝胶含量增加。而硅烷单体与接枝助剂的最佳量之比为1 :1。通过PP改性前后的力学性能和发泡性能对比研究表明,接枝和交联使改性后PP的耐热性、抗冲击性、拉伸性能均有所改善;而且用改性PP发泡可以获得泡孔均匀、细密,且具有独立泡孔的高质量泡沫塑料。     

PETA熔融接枝PP/LDPE共混物的研究

研究了季戊四醇三丙烯酸酯熔融接枝PP／LDPE共混物体系中，各因素对产物熔体质量流动速率和熔体强度的影响，并对产物拉伸粘度和化学接枝情况等进行了测试及表征，实验结果表明，引发剂用量较低，单体用量较高时，产物的熔体质量流动速率小,熔体强度较高，拉伸粘度较大，且在拉伸过程中，产生了应变硬化效应；随着单体用量的增加，接枝率会有所上升。     

原材料对硅烷接枝交联高熔体强度聚丙烯流动性能影响的研究

采用不饱和硅烷为接枝单体,不饱和烯烃为共单体,在双螺杆挤出机上实现均聚型聚丙烯的接枝交联,制得了高熔体强度聚丙烯。实验通过熔体指数(MFR)和凝胶含量的变化研究原材料对改性PP的影响。结果显示,体系中的试剂均严重影响材料的熔体流动性能。在硅烷和共单体共存的条件下,材料的熔体流动性能随引发剂A含量的增加而下降。共单体起到稳定大分子自由基的作用,增加了硅烷的接枝效率和接枝速率,共单体与硅烷最佳摩尔比为1∶1。改性后材料的耐热性、力学性能等均有较大提高。     

双马来酰亚胺熔融接枝聚丙烯的研究

以二叔丁基过氧化物(DTBP)为引发剂,采用双官能团极性单体双马来酰亚胺(BMI)对聚丙烯(PP)进行熔融接枝改性,用红外光谱对接枝反应进行了表征,并分析了BMI对PP接枝率的影响。考察了引发剂用量、单体用量对PP流动性能、冲击性能和热稳定性能的影响。结果表明:PP接枝率随着BMI用量的增加而增大,最高可达37.5%;在DTBP用量为0.1～0.2份时,通过调整BMI用量,PP的熔体流动速率可在30～90 g/10min范围内调节并,使其冲击强度维持在22 J/m左右;BMI的接枝可以提高PP的热稳定性能。     

固相接枝法制备高熔体强度聚丙烯的研究

采用聚丙烯(PP)粉料,以过氧化苯甲酰(BPO)为引发剂,多官能团单体季戊四醇三丙烯酸酯(PETA)为接枝剂,通过固相接枝法制备了高熔体强度PP。研究表明,抗氧剂的加入能有效控制固相接枝反应中的降解,当BPO的用量为0.05份,PETA的用量为1.6份,抗氧剂用量为0.4份时,PP粉料的熔体流动速率从改性前的9.0 g/10 min下降到0.9 g/10 min;采用测重法测定的熔体强度为2.56 g,而改性前PP的熔体强度小于0.05 g。采用改性后的PP粉料进行模压发泡,发泡密度可达0.12 g/cm3。     

1,6-己二醇二丙烯酸酯和顺丁烯二酸酐的配比对接枝聚丙烯结构与性能的影响

以过氧化二异丙苯(DCP)为引发剂,1,6-己二醇二丙烯酸酯(HDDA)和顺丁烯二酸酐(MAH)作为单体,通过熔融挤出制备长支链结构的聚丙烯。主要研究了单体配比对改性聚丙烯(PP)的熔体流动速率、熔体强度和力学性能的影响,测定了改性产物的凝胶含量、流变性能和相对接枝率,并通过红外光谱和示差扫描量热仪等对接枝产物进行表征。结果表明,双单体接枝改性PP的熔体强度有所提高,当HDDA和MAH的质量比为1∶0.50时,改性PP的熔体强度为44.4kPa·s,是纯PP的2倍左右,其力学性能和剪切流变性能有所改善。     

反应挤出法制备高熔体强度聚丙烯

以1,6己二醇二丙烯酸酯（HDDA）为接枝单体,苯乙烯（St）为共聚单体对聚丙烯（PP）进行熔融接枝,并在反应体系中加入β成核剂,从而改变PP晶型,通过接枝长支链提高聚丙烯的熔体强度。研究了螺杆转速、引发剂用量、单体摩尔比及投料量对熔体流动速率和熔体强度的影响。采用傅里叶变换红外光谱仪、热重分析仪及X射线衍射仪等对改性材料的结构和性能进行分析。结果表明,在优化的反应条件下,接枝改性PP的熔体流动速率和熔体强度分别为0.70 g/10 min,10.00 kPa·s;热稳定性也比纯PP有很大程度提高。     

反应挤出法制备高熔体强度聚丙烯的研究

采用不饱和硅烷为接枝单体,不饱和烯烃为交联助剂,在双螺杆挤出机上一步法实现了均聚型聚丙烯(PP)的接枝交联,制得了高熔体强度PP。结果表明,接枝单体、交联助剂、引发剂均显著地影响PP的熔体流动性能。在硅烷和交联助剂共存的条件下,PP的熔体流动性能随引发剂过氧化苯甲酰(BPO)用量的增加而下降。交联助剂起到稳定大分子自由基的作用,增加了硅烷的接枝效率和接枝速率;并指出硅烷接枝交联法是目前制备高熔体强度PP方法中最有希望实现工业化生产的技术。     

一步法硅烷接枝交联改性聚丙烯的研究

采用反应挤出法一步实现聚丙烯（PP）的硅烷接枝和交联改性，制备出了具有部分交联结构的高熔体强度PP。通过改性前后红外光谱、熔体流动性能、凝胶含量、结晶行为、力学性能和发泡性能的变化考察了改性对材料性能的影响。结果表明，一步法改性后PP大分子中引入了硅烷接枝交联结构，使熔体强度、熔体黏度提高，熔体流动速率显著降低，并且体系中出现了高达48％的凝胶；交联结构的引入使PP的结晶速率减缓；改性后材料的力学性能有所提高，而发泡性能大大改善，可以获得高质量的泡沫塑料。     

Study of multi‐monomer melt‐grafting onto polypropylene in an extruder

Free‐radical melt‐grafting of the dual‐monomer systems glycidyl methacrylate–styrene (GMA‐St) and hydroxyethyl methacrylate–styrene (HEMA‐St) onto polypropylene (PP) has been studied using a single‐screw extruder. For single monomer grafting systems, degradation of PP was unavoidable and deterioration of the mechanical properties of the grafted PP subsequently occurred because of β‐scission of PP chains during the free‐radical melt‐grafting process. However, for the dual‐monomer systems, it is shown that the addition of styrene as a comonomer can significantly enhance the GMA or HEMA grafting levels on PP and reduce the extent of β‐scission of PP backbone. It has been found that the grafting degree of dual‐monomer melt‐grafted PP, such as PP‐g‐(GMA‐co‐St) or PP‐g‐(HEMA‐co‐St), is about quadruple that of single‐monomer grafted PP for the same monomer and dicumyl peroxide concentrations. Moreover, the melt flow rate of the dual‐monomer grafted PP is smaller than that of the unmodified PP. Hence, PP not only was endowed with higher polarity, but also kept its good mechanical properties. © 2000 Society of Chemical Industry     

Influence of polyfunctional monomer on melt strength and rheology of long‐chain branched polypropylene by reactive extrusion

Long chain branching (LCB) were added to linear polypropylene (PP) using reactive extrusion in the presence of selected polyfunctional monomers (PFMs) and a peroxide of dibenzoyl peroxide (BPO). Fourier Transformed Infrared spectra (FTIR) directly confirmed the grafting reaction occurred during the reactive extrusion process. Various rheological plots including viscosity curve, storage modulus, Cole‐Cole plot, and Van‐Gurp plots, confirmed that the LCB structure were introduced into modified PPs skeleton after modification. In comparison with linear PP, the branched samples exhibited higher melt strength, lower melt flow index, and the enhancement of crystallization temperature. The LCB level in modified PPs and their melt strength were affected by the type of PFM used and could be controlled by the PFM properties and structure. PFMs with lower boiling points, such as 1, 4‐butanediol diacrylate (BDDA), could not produce LCB structure in modified PP skeleton. The shorter molecular chain bifunctional monomers, such as 1,6‐hexanediol diacrylate (HDDA), favored the branching reaction if their boiling points were above the highest extrusion temperature. And some polar groups, such as hydroxyl, in the molecule of PFM were harmful to the branching reaction, which might be attributed to the harm of the polarity of groups to the dispersion of PFM in PP matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

GMA/St双组分单体熔融接枝聚丙烯的研究

分别以甲基丙烯酸缩水甘油酯（GMA）和马来酸酐（MAH）为接枝单体，苯乙烯（St）为接枝共单体，过氧化二异丙苯（DCP）为引发剂对聚丙烯（PP）进行熔融接枝，研究了接枝单体的种类、组分配比等因素对PP的接枝率和熔体流动速率等的影响，并研究了接枝PP的力学性能和耐热变形性能。实验结果表明：作为接枝单体，GMA比MAH更具有优越性；双组分单体熔融接枝PP的接枝率和性能优于单组分单体熔融接枝；接枝PP的结晶参数受其接枝率的影响；当PP／GMA／St／DCP=100／6／3／0、3时，PP—g^-（GMA—CO—St）的接枝率最高，力学性能和耐热变形性能最好。     

Rheology and thermal behavior of long branching polypropylene prepared by reactive extrusion

Long‐chain branching polypropylene (LCB‐PP) was achieved by reactive extrusion in the presence of bifunctional monomer [1,6‐hexanediol diarylate (HDDA)] and peroxide of dicumyl peroxide (DCP). Influences of HDDA and DCP concentrations on the branching efficiency were comparatively evaluated. Fourier transformed infrared spectroscopy (FTIR) results indicated that the grafting reaction took place, and HDDA has been grafted on PP skeleton. In comparison with initial PP, some modified samples showed lower melt flow index because of a large number of LCB in their skeleton. Several rheology plots were used to investigate the rheological properties of the initial PP and modified PPs, and the rheological characteristics confirmed the LCB in modified PPs skeleton. DSC results showed that the crystallization temperatures of modified PPs were higher than those of initial PP and degraded PP, suggesting that the modified PPs had long‐chain branched structure. The contrastive investigation in the rheology of modified PPs suggested that proper concentrations of HDDA and DCP were more beneficial to producing LCB during reactive extrusion. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

长链支化聚丙烯的制备及其熔体流变性能的研究

在过氧化物引发剂和季戊四醇三丙烯酸酯存在下,利用反应挤出法制备了长链支化聚丙烯(LCB-PP)。采用熔体流动速率(MFR)仪、旋转流变仪和熔体强度测试仪对纯聚丙烯(PP)及其改性PP进行测试与表征。讨论了不同的过氧化物引发剂对改性PP流变性能的影响。结果表明,采用过氧化苯甲酰时,改性PP具有较高的熔体强度、较低的MFR,并且在低频处储能模量增大。同时发现,随温度的升高,改性PP的熔体强度逐渐降低,但升高到一定温度后,熔体强度的变化不明显。     

油酸熔融接枝聚丙烯的研究

系统地研究了油酸这一长链不饱和脂肪酸熔融接枝聚丙烯（ＰＰ）,探讨了反应条件（如转速、反应温度、反应时间）、引发剂类型及浓度、单体浓度、加入第２单体（苯乙烯）等因素对接枝反应的影响。采用红外光谱表征了ＰＰ接枝产物,并用差示扫描量热法研究了接枝前后ＰＰ结晶性能的变化。     

A study of radical graft copolymerization on polypropylene during extrusion using two peroxide initiators

Functionalization of polypropylene (PP) during melt extrusion has been explored extensively. In this study, two different radical initiators were employed and compared in grafting acyclic halamine precursors to PP. 2,4‐Diamino‐6‐diallylamino‐1,3,5‐triazine (NDAM) was grafted onto PP during a melt‐extrusion process using either 2,5‐dimethyl‐2,5‐(tert‐butylperoxy)hexyne (DTBHY) or dicumyl peroxide (DCP) as initiator. The results confirmed the radical graft copolymerization of the monomer onto the PP backbone during the reactive extrusion process. It was revealed that, at low monomer concentration, when peroxide initiator concentration was increased, polymer chain scission became dominant. DCP was more efficient than DTBHY as an initiator in the graft polymerization. After exposure to chlorine bleach, the grafted structures could be easily transformed into N‐halamines, which provided powerful, durable and regenerable antibacterial activities against Escherichia coli and Staphylococcus aureus. It is concluded that both DCP and DTBHY could be used as radical initiators in reactive extrusion to graft certain vinyl monomers to PP. The NDAM‐grafted PP could provide expected antibacterial function after chlorination of the grafted product in a chlorine bleach solution. The modified PP showed great potential for use in medical devices and non‐woven textiles. Copyright © 2009 Society of Chemical Industry     

马来酸酐及苯乙烯同时接枝聚丙烯的研究

用过氧化二异丙苯(DCP)作为引发剂，采用双螺杆反应挤出的苯乙烯、马来酸酐2种单体同时接枝聚丙烯．研究了单体总浓度、单体比例、引发剂浓度对PP的接枝率、接枝效率和熔体流动速率的影响。通过实验发现苯乙烯的加入使接枝率和接枝效率比单独的马来酸酐接枝都有很大的提高。     

Influence of grafting formulations and extrusion conditions on properties of silane‐grafted polypropylenes

The melt grafting of unsaturated silanes onto powdered polypropylene (PP) in a Haake TW100 twin‐screw extruder and curing in hot water were studied. The influence of grafting formulations and extrusion conditions on the melt flow rates of grafted PP and the gel percentages of crosslinked PP was investigated. The gel percentages of methacryloylpropyltrimethoxysilane (VMMS)‐grafted PP were markedly higher than those of vinyltriethoxysilane (VTES)‐ and vinyltrimethoxysilane (VTMS)‐grafted PP, while significantly less degradation of PP during grafting was observed for VMMS‐grafted PP. When benzoyl peroxide (BPO) was used as an initiator, no degradation of PP during grafting was observed, and the melt flow rates of grafted PP decreased with increasing BPO concentration. In contrast, use of dicumyl peroxide (DCP) as an initiator resulted in severe degradation of PP, and the melt flow rates of grafted PP increased gradually with increasing DCP concentration. BPO resulted in higher gel percentages than those of DCP at a fixed initiator concentration. Introduction of styrene into the grafting system greatly improved the gel percentage of crosslinked PP and reduced the degradation of PP during grafting. The optimum molar ratio of styrene to monomer is at about 1.5:1. Relatively low processing temperatures and high screw speeds are favorable. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1233–1238, 2000     

发泡用高熔体强度聚丙烯的研究

以过氧化苯甲酰(BPO)为引发剂,在同向双螺杆挤出机上对聚丙烯(PP)进行硅烷交联,制备了高熔体强度聚丙烯(HMSPP),然后制得高发泡倍率的PP制品.实验对改性PP的熔体强度、力学性能、热性能和发泡性能进行了表征.结果表明:自制HMSPP的熔体强度是纯PP的5.01倍,力学性能和耐热性与纯PP相比均有较大提高,可用于成型高发泡倍率制品.