溶剂热法制备AS接枝马来酸酐的研究

以马来酸酐(MAH)为单体、苯乙烯(St)为共单体、过氧化二异丙苯(DCP)为引发剂,采用溶剂热法分别制备了苯乙烯-丙烯腈共聚物(AS)接枝物AS-g-MAH以及AS-g-(MAH-St).利用红外光谱对接枝物进行了结构表征,证明MAH已经成功接枝在AS链上.并用反式滴定法测定了接枝率,讨论了引发剂用量、马来酸酐用量、反应温度、反应时间、反应物浓度和共单体用量对接枝率的影响.结果表明:随着引发剂用量的增加和反应时间的延长,接枝率先增大,然后趋于平稳;随着马来酸酐用量、反应温度和反应物浓度的增加,接枝率先增大后下降;共单体苯乙烯的加入对接枝率的提高有很大的促进作用.     

Preparation and properties of bitumen modified with the maleic anhydride grafted styrene‐butadiene‐styrene triblock copolymer

A procedure to improve the properties of styrene‐butadiene‐styrene (SBS) copolymer modified bitumen by grafting of maleic anhydride (MAH) onto SBS in the presence of benzoyl peroxide (BPO) as initiator was proposed. The effects of the grafting degree (GD) on the properties of modified bitumen were investigated. FTIR spectroscopy was employed to verify the grafting of MAH onto SBS. The GD of MAH onto SBS was determined by a back titration procedure. To assess the effects of the GD of grafted SBS on properties of modified bitumen, the softening point, penetration, ductility, elastic recovery, penetration index, viscosity, storage stability, and dynamic shear properties were tested. Experimental results indicated that the SBS grafted with maleic anhydride (SBS‐g‐MAH) copolymer was successfully synthesized by solvothermal method, and different GD of the SBS‐g‐MAH was obtained by control the MAH concentration. The GD of the MAH onto SBS has great effect on the rheological properties of the modified bitumen, and the high temperature performance and storage stability of modified bitumen were improved with the GD of the MAH onto SBS increasing. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Styrene‐assisted free‐radical graft copolymerization of maleic anhydride onto polypropylene in supercritical carbon dioxide

The free‐radical graft copolymerization of maleic anhydride (MAH) onto polypropylene (PP) with the assistance of styrene (St) in supercritical carbon dioxide (CO₂) was studied. The effects of the St concentration and initiator concentration on the functionality degree of the grafted PP in supercritical CO₂ were investigated. The addition of St drastically increased the MAH functionality degree, which reached a maximum when the molar ratio of MAH and St was 1:1. St, an electron‐donating monomer, could interact with MAH through charge‐transfer complexes to form the St–MAH copolymer (SMA), which could then react with PP macroradicals to produce branches by termination between radicals. There was SMA in the grafting reaction system characterized by Fourier transform infrared and differential scanning calorimetry. Furthermore, the highest MAH functionality degree was obtained when the concentration of 2,2′‐azobisisobutyronitrile (AIBN) was 0.6 wt % based on PP. The effects of the temperature and pressure of supercritical CO₂ on the functionality degree of the grafted PP were analyzed. An increase in the temperature accelerated the decomposition rate constant of AIBN, thereby promoting the grafting reaction. In addition, an increase in the temperature increased the diffusion of monomers and radicals in the disperse reaction system of supercritical CO₂. The highest degree of functionality was found at 80°C. Also, the functionality degree of grafted PP decreased with an increase in the pressure of supercritical CO₂ within the experimental range. The morphologies of pure PP and grafted PP were significantly different under polarizing optical microscopy. The PP spherulites were about 38 μm in size, and the grafted PP spherulites were significantly reduced because of heterogeneous nucleation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 853–860, 2003     

Synthesis and characterization of solid‐phase graft copolymer of polypropylene with styrene and maleic anhydride

Polypropylene (PP) was modified by solid‐phase graft copolymerization with maleic anhydride (MAH) and styrene (St), using benzoyl peroxide as the initiator and xylene as the interfacial agent. Effects of various factors such as monomer concentration, monomer ratio, initiator concentration on grafting percentage, and acid value were investigated. The graft copolymer was characterized by Fourier transform infrared, pyrolysis gas chromatography—mass spectroscopy, and dynamic mechanical analysis, and the intrinsic viscosity of the extractive from the reaction product was investigated. The results showed that the grafting percentage and acid value of the graft copolymer of PP with two monomers (MAH and St) were considerably higher than those of the graft copolymer of PP with MAH alone. The graft segments were shown to be the copolymer of St and MAH with a substantial molecular weight. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2482–2487, 2000     

Ultrasound initiated maleic anhydride grafted onto a novel polypropylene copolymer

The reaction of maleic anhydride (MAH) grafted onto propylene‐based copolymer (DP) without adding any initiator was conducted through ultrasound assisted extrusion in this article. The effects of ultrasound power, die temperature, and MAH content on the grafting degree and efficiency were studied. With increasing ultrasound power, the grafting degree and efficiency of DP‐g‐MAH increase. The presence of ultrasound with higher power and lower die temperature is beneficial to increase the grafting degree and efficiency. The increase of MAH content can increase the grafting degree but reduce the grafting efficiency. Based on the results of melt flow index, dynamical rheological, gel permeation chromatograph (GPC), and Fourier transform infrared spectroscopy (FTIR) tests, the mechanisms of the grafting reaction were proposed. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

悬浮接枝共聚合成POE-g-MAS及其对SAN树脂的增韧作用

合成了乙烯-辛烯共聚物(POE)和甲基丙烯酸甲醋(MMA)-丙烯腈(SAN)-苯乙烯(St)的接枝共聚物(POE-g-MAS)。研究了单体比率、POE/单体比率和引发剂浓度等因素对接枝共聚合反应的影响。聚合产物用丙酮抽提得到接枝共聚物POE-g-MAS,傅里叶变换红外光谱分析证明MMA-AN-St已经接枝在POE分子链上。用POE-g-MAS与Stet树脂共混制备了具有高抗冲性能的POE-g-SAN/SAN共混物,并用扫描电镜观察共混物的冲击断面,探讨了其增韧机理。     

Melt grafting of maleic anhydride onto polypropylene with 1‐decene as a second monomer

The influence of 1‐decene as the second monomer on the melt‐grafting behavior of maleic anhydride (MAH) onto polypropylene (PP) was studied with differential scanning calorimetry and Fourier transform infrared spectroscopy. We found that the value of the grafting degree increased from 0.68% for pure MAH‐g‐PP to 1.43% for the system with a 1‐decene/MAH molar ratio of 0.3, whereas the maximum value with styrene (St) as the second monomer was 0.98% under an St/MAH molar ratio of 1.0. Compared with the contribution of St/MAH‐g‐PP to the peeling strength between the PP and polyamide (PA) layer for a PP/PA laminated film, the introduction of 1‐decene/MAH‐g‐PP increased the peeling strength from 180 g/15 mm to 250 g/15 mm. 1‐Decene inhibited the chain scission behavior of PP. 1‐Decene reacted with MAH to form a 1‐decene/MAH copolymer or the Alder‐ene reaction product before the two monomers grafted onto PP. The grafting of the reactive product onto PP greatly improved the grafting degree of MAH. What is more, because of the similar chemical structures of 1‐decene and PP, the affinity of 1‐decene with PP was higher than that of St. Compared with St, the introduction of less 1‐decene led to a higher grafting degree and higher peeling strength. Therefore, we concluded that 1‐decene was more effective for improving the grafting degree of MAH onto PP. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and reaction kinetics model of suspension phase grafting polypropylene with dual monomers

The grafting polymerization of maleic anhydride (MAH) and styrene (St) onto PP was carried out in suspension phase. Infrared (IR) spectra and ¹H-NMR spectra confirmed that MAH and St were successfully grafted onto the PP backbone. The influences, such as monomers concentration, reaction temperature, initiator concentration and reaction time, on the grafting polymerization rate were also studied, and then the polymerization model was obtained to describe the polymerization regularities. The results showed that the model was adequate to reflect the courses, and diffusion and equilibrium adsorption played an important role in suspension polymerization.     

STUDY ON THE GRAFT REACTION OF MALEIC ANHYDRIDE ONTO METALLOCENE-BASED POLYETHYLENE–OCTENE ELASTOMER

Grafting of maleic anhydride (MAH) onto metallocene based polyethylene–octene elastomer (POE) was studied in this article. By the results of Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and differential scanning calorimetry (DSC), it was confirmed that POE was grafted with MAH but the crosslinking reaction was accompanied by the predominant graft reaction due to a competition of POE macro-radical and excited MAH. Effects of various parameters such as monomer loading, initiator loading, and reaction time on grafting percentage and gel yield were also investigated. It was also found that the grafting percentage and the gel yield, at equilibrium, were both higher for POE containing lower degree of comonomer content. From the result of DSC characterization, it was shown that the change of crystallinity is slight for POE-g-MAH copolymer when the gel was removed from the copolymer. So one thought that the effect of gel formation on the properties of POE-g-MAH can be neglected due to the low gel yield. It was also proved that strength and elongation at break are both decreased while the grafting percentage was increased. Finally, the method proposed in this research can produce POE-g-MAH copolymer with low gel.     

Enhancement of graft yield and control of degradation during polypropylene maleation in the presence of polyfunctional monomer

Free‐radical initiated grafting of maleic anhydride (MAH)/polyfunctional acrylate (PFA) multimonomer system onto polypropylene (PP) via reactive extrusion was studied. The effects of PFA and initiator concentration on the grafting reaction were investigated. It was shown that PFA as a comonomer could greatly enhance MAH grafting degree, which increased monotonically as the molar ratio of PFA to MAH increased. The rheology test demonstrated that the viscosity of grafted PP was also promoted as more PFA was used. The formation of branched structure during the grafting process was proved by oscillatory shear rheological analysis. The mechanism of grafting in the presence of PFA was discussed, suggesting PFA had higher reactivity with PP macroradicals than MAH and therefore forming stabilized macroradicals, thus resulting in depression of β‐scission and favoring the formation of branched structure. Higher initiator concentration gave higher MAH grafting degree but more severe degradation. The mechanical properties of the grafted PP were comparable with those of unmodified PP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

苯乙烯存在下马来酸酐熔融接枝聚丙烯的研究

分别在哈克流变仪（Haake）和双螺杆挤出机（TSE）中,研究了苯乙烯（St）存在下马来酸酐（MAH）熔融接枝聚丙烯（PP）的过程。讨论了过氧化二异丙苯（DCP）用量、St用量、MAH用量、反应时间、反应温度、螺杆转速以及反应器型式对接枝反应的影响．实验发现：随DCP用量的增加,MAH的接枝率先增加后减小,熔体流动速率（MFR）一直增加;保持MAH用量不变增加St用量时,MAH的接枝率在MAH与St的摩尔比为1：1时达到最大,MFR却一直减小;保持St用量不变增加MAH用量,MAH的接枝率先增加后略有减小,MFR却存在极大值;随反应时间的增加,MAH的接枝率与MFR都先增加后减小;温度过高,MAH的接枝率降低,PP热降解较严重;螺杆转速较低时,MAH的接枝率较低,螺杆转速较高时,PP降解增加;在TSE中的MAH接枝率比Haake中的低,但降解比Haake中的小得多。     

POE/PP的接枝改性及在制备超韧尼龙中的应用研究

研究了在含有适量聚丙烯的聚烯烃弹性体乙烯-1-辛烯共聚物(POE)熔融接枝马来酸酐(MAH)反应中,引发剂、接枝单体用量、及阻交联剂品种对接枝率的影响及其微观机理。结果表明:控制体系引发剂的含量是获取高接枝率的关键,当DCP的加入量为0.25%,MAH的含量为1.2%时,体系的接枝率达1%左右,从熔体流动速率来看体系未出现明显交联。同时探讨了接枝物在超韧尼龙合金制备中的应用效果。     

Dynamic rheological and morphological study of the compatibility of thermoplastic polyurethane/ethylene–octene copolymer blends

Two grafted ethylene–octene copolymers [POEs; i.e., POE‐g‐maleic anhydried (MAH) and aminated POE (denoted by POE‐g‐NH₂) were used as compatibilizers in immiscible blends of thermoplastic polyurethane (TPU) and POE. The effects of the compatibilizers on the dynamic rheological properties and morphologies of the TPU/POE blends were investigated. The characteristic rheological behaviors of the blends indicated that the strong interactions between the two phases were due to the compatibilization. Microstructural observation confirmed that the compatibilizers were located at the interface in the blends and formed a stable interfacial layer and smaller dispersed phase particle size. Compared with POE‐g‐MAH, POE‐g‐NH₂ exhibited a better compatibilization effect in the TPU/POE blends. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Solvothermal process for grafting dibutylmaleate onto poly(ethylene‐co‐1‐octene)

Solvothermal process was successfully developed to graft dibutylmaleate (DBM) onto poly(ethylene‐co‐1‐octene) (POE) with dicumyl peroxide (DCP) as free radical‐initiator. FTIR spectra demonstrate that DBM is successfully grafted onto the backbone of POE by this novel method. The influences of DBM content, DCP concentration, POE concentration, reaction temperature and reaction time on the grafting copolymerization have been investigated in detail through grafting degree (GD). It is worthy to indicate that high grafting degree (above 15%) can be achieved through the one‐pot way when the graft reaction is carried out in 40 mL toluene at 150°C for 5 h with 1.6 g DBM, 6–8 g POE and 0.35 g DCP. This developed solvothermal process is becoming an effective way to prepare POE‐g‐DBM graft copolymers, and can be extended to other systems. In addition, TGA results show that the thermal properties of POE are enhanced after the grafting reaction. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Melt grafting of maleic anhydride onto elastomeric ethylene‐octene copolymer by reactive extrusion

Melt grafting of maleic anhydride onto elastomeric ethylene‐octene copolymer was carried out in a twin‐screw extruder, in the presence of dicumyl peroxide as an initiator. Dimethyl formamide was used as an inhibitor to reduce crosslinking and as a solvent for peroxide initiator. The aim of the work is to produce the copolymer with reactive functionality without the expense of elastomeric characteristics. Particular consideration was, therefore, given to the effects of initiator and monomer concentrations, and of screw speed on the degree of grafting, percentage of conversion, amount of crosslinked products, and on the stress‐strain behaviors of the grafted products. The degree of grafting was found to be dependent mainly on the initiator and monomer concentrations. Increasing the initiator concentration increased the degree of grafting, and at the same time, increased the amount of gel (crosslinking). An increase in gel content of the grafted products resulted in a change of tensile behaviors from uniform deformation followed by strain‐hardening at high strains to low extensibility and fracture at low strains.     

聚烯烃弹性体与马来酸酐的熔融接枝

以双螺杆挤出机作为反应器，比较了聚烯烃弹性体（POE），线性低密度聚乙烯（LLDPE）与马来酸酐（MAH）的熔融接枝反应。尽这两种树脂具有相近的支化度，但由于POE树脂的大支链对大分子自由基之间的偶合反应具有抑制作用，所以，POE/MAH接枝体系的接枝率明显高于LLDPE／MAH接枝体系，而且接枝产物保持了较好的流动性；酸酐在POE树脂上的接枝率随过氧化物和接枝单体用量的增加而增大。接枝树脂可以明显提高PE与铝之间的粘接强度。     

线性低密度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,在双螺杆挤出机中进行了马来酸酐(MAH)熔融接枝线性低密度聚乙烯(LLDPE)的研究,用红外光谱表征了接枝反应的存在。考察了引发剂用量、单体用量、螺杆转速以及温度对接枝反应的影响,并探讨了苯乙烯(St)作共单体对接枝反应的影响。研究表明:在引发剂含量较低时,用苯乙烯作共单体能够显著提高接枝率。     

Melt grafting of poly(ethylene‐vinyl acetate) copolymer with maleic anhydride

Poly(ethylene‐vinyl acetate) (EVA) copolymer was melt grafted with maleic anhydride (MAH) in a twin screw extruder in the presence of peroxide. It is confirmed that MAH has been melt grafted on the backbone of EVA by FTIR using the method of hydrolysis. The NMR analysis suggests that the grafting reaction occurs on the tertiary carbon of main chain of EVA other than the methyl moiety of vinyl acetate (VA) group. The incorporation of VA groups onto the matrix shows a competitive effect on the grafting. The existence of VA groups promotes the extent of MAH graft onto EVA; nevertheless, it also weakens the crystallizability of main chain. When the content of peroxide initiator is 0.1 wt % based on the polymer matrix, the grafting degree increases with increasing the concentration of monomer. When the peroxide content is higher than 0.1 wt %, side reactions such as crosslinking or disproportionation will be introduced into this system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 841–846, 2006     

Properties of poly(ethylene 1‐octene)‐g‐maleic anhydride copolymers prepared via solvothermal process

The poly(ethylene 1‐octene)‐g‐maleic anhydride copolymers (POE‐g‐MAH) with high grafting degree (GD) (>9%) have previously been obtained by a solvothermal method in our laboratory. It is found that the low GD (less than 2.5%) did not change the bulk properties of polyolefine elastomers (POE). Thereforefore, it is worth further understanding whether a high GD POE‐g‐MAH copolymer differs from the pure POE in its comprehensive properties and performance. In this article, POE‐g‐MAH with different GDs were synthesized and characterized by thermogravimetric analyze (TGA), differential scanning calorimetry (DSC), wide angle X‐ray diffraction spectroscopy (WAXD), and dynamic rheological testing. The results show that the thermal decomposition temperature, melting points, the crystallization temperatures, and the crystallinities were decreased by the increasing GD. By WAXD, three peaks respectively, attributed to the amorphous phase, the (110) and (200) interferences of the orthorhombic unit cell were detected, and they also decreased by the increasing GD. And the POE‐g‐MAH copolymers had higher storage modulus (G′), loss modulus (G″), and complex viscosity (η*) than those of pure POE. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

马来酸酐熔融接枝EPDM的研究

在哈克流变仪（Haake）中,研究了以2,5-二甲基-2,5-双（叔丁基过氧基）己烷（DHBP）为引发剂,在苯乙烯（St）存在下,马来酸酐（MAH）熔融接枝三元乙丙橡胶（EPDM）的过程。产物用傅立叶红外光谱仪进行了表征,并用化学滴定法测定了MAH的接枝率。讨论了St用量、MAH用量、DHBP用量、反应时间、反应温度和转速对接枝反应的影响。实验发现：MAH用量为2phr时,MAH的接枝率能达到1.53%;MAH的用量不宜过高;DHBP的用量不宜超过0.2phr。