Ultrasound initiated functionalization of SEBS with maleic anhydride

The functionalization of styrene‐b‐(ethylene‐co‐1‐butene)‐b‐styrene tri‐block copolymer with maleic anhydride (MAH) in melt state through ultrasound initiation was studied in this article. The effects of plasticizer content and types, MAH content, ultrasound power, and die temperature on grafting ratio of MAH were investigated by means of acid–base titration. Functionalized products were confirmed by new absorption bands in Fourier‐transform infrared spectroscopy. The experimental results showed that the ultrasound initiated products had lower complex viscosity (η^*), lower gel content as well as lower molecular weight than peroxide initiated products, indicating that the ultrasound could cause chain scission and suppress the crosslinking side reaction to gain functionalized products, which have less gel content and high grafting ratio. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Functionalization of ethylene–propylene–diene monomer rubber with maleic anhydride in the melt state through high‐shear stress‐induced initiation

The functionalization reactions of ethylene–propylene–diene monomer rubber (EPDM) with maleic anhydride (MAH) in melt state through high‐shear‐stress‐induced initiation by an increase in the screw rotation speed of the twin‐screw extruder and through compounded initiation by the addition of some initiator and an increase in the screw rotation speed were investigated. The results show that, with increasing screw rotation speed and reaction temperature, the percentage grafting and melt flow rate of the functionalized products (EPDM‐g‐MAH) were noticeably increased, and the viscosity‐average molecular weight decreased, which implied that the grafting reaction consisted of the chain scission and grafting reaction of the produced macroradicals with MAH. In the presence of a certain peroxide initiator, the crosslinking reaction during melt extrusion was suppressed by an increase in the screw rotation speed. The percentage grafting of EPDM‐g‐MAH amounted to 1.1%, its melt flow rate was between 0.3 and 4.0 g/10 min, and its gel content was less than 1.0%, depending on the screw rotation speed and reaction temperature. Impact testing and scanning electron microscopy showed that the functionalized product prepared through the high shear stress‐induced initiation had a higher blocking activity with the amide terminated of PA66 than that prepared through the peroxide initiation or through the compound initiation, and the impact strength of the PA66/EPDM blends, improved by the high‐shear‐stress‐induced product was noticeably higher than those of the peroxide‐initiated product or the compound‐initiated one. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Reactive compatibilization of the poly(butylene terephthalate)–EVA blend by maleic anhydride. II. Correlations among gel contents,grafting yields,and mechanical properties

Correlations among the degree of crosslinking of ethylene vinyl acetate copolymer (EVA), the grafting yield of maleic anhydride (MAH) onto EVA, and the mechanical properties of the blends of poly(butylene terephtalate) (PBT) with EVA‐g‐MAH were investigated. The EVA was functionalized by melt grafting reaction in the presence of MAH and dicumyl peroxide (DCP) using a plasticorder. The grafting yield of MAH was increased by increasing the concentration of MAH and DCP. The flexural strength of PBT–EVA‐g‐MAH blends depends on both the grafting yield of MAH and the degree of crosslinking of EVA, while the crosslinked parts of EVA‐g‐MAH hindered rather than improved the tensile strength regardless of the increase of the grafting yield of MAH. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1305–1310, 2003     

Modification of acrylonitrile‐butadiene‐styrene terpolymer by graft copolymerization with maleic anhydride in the melt. II. Properties and phase behavior

The graft copolymerization of maleic anhydride (MAH) onto acrylonitrile‐butadiene‐styrene terpolymer (ABS) using dicumyl peroxide and benzoyl peroxide as the binary initiator and styrene as the comonomer in the molten state was described. The properties and phase morphologies of the modified products (ABS‐g‐MAH) were studied. The results indicate that the melt flow index (MFI) of ABS‐g‐MAH increases with the increase of MAH content, the initiator concentration, and the screw speed, whereas the MFI decreases with the increase of temperature. The impact strength and the percentage elongation of ABS‐g‐MAH both decreased and the tensile strength of ABS‐g‐MAH increased slightly as the grafting degree increased. The phase inversion behavior of the modified product was observed by transmission electron microscopy. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2834–2839, 2004     

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     

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     

Maleic anhydride/styrene melt grafting and crosslinking onto ethylene‐octene copolymer

Melt grafting of the multimonomer system of maleic anhydride (MAH)/styrene (St) onto ethylene‐octene copolymer (POE) was performed by a twin‐screw extruder. The effects of St and initiator contents as well as MAH/St on the grafting reaction were investigated. The structure and properties of the grafted POE were characterized by the Fourier transform infrared spectroscopy, melt flow index, dynamic rheological behaviors, and thermogravimetric analysis. It is shown that the addition of St can significantly enhance MAH grafting degree onto POE. MFI values of grafted POE are affected not only by MAH/St copolymer concentration, but also by initiator concentration. These data indicate that the interaction and reaction between MAH and St monomers plays an important role in the grafting reaction. St improves the grafting reactivity of MAH and reacts with MAH before the two monomers graft onto POE. And high grafting degree can be obtained while the gel content is still low. Compared with neat POE, grafted POE shows different dynamic rheological behaviors and high thermal stability. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

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     

Functionalization of high density polyethylene with maleic anhydride in the melt state through ultrasonic initiation

Grafting of maleic anhydride (MAH) onto high density polyethylene (HDPE) performed in the melt state through ultrasonic initiation by a laboratory‐scale ultrasonic extrusion reactor was studied in this paper. The effect of sonic intesity on the amount of grafted MAH, viscosity‐average molecular weight and melt flow index of the grafted product was investigated. The results show that the ultrasonic waves can obviously decrease the molecular weight of the grafted product and cause the increase of the amount of grated MAH, implying that the grafting reaction consists of the chain scission and the grafting reaction of the produced macroradicals with MAH. The percentage of grafting of the product amounts to 0.6%; its melt‐flow index is between 0.5 and 2.0 g/10 min, depending upon ultrasonic intensity, MAH content and grafting temperature. Compared with the method of peroxide initiation, in this method the crosslinking reaction can be prevented easily through the allocation of ultrasonic intensity. The mechanical properties of the improved HDPE/GF composite produced by ultrasonic initiatives are higher than in those produced by peroxide initiatives.     

Graft copolymerization of maleic anhydride onto low‐molecular‐weight polyisobutylene through solvothermal method

The free‐radical graft copolymerization of maleic anhydride (MAH) onto highly reactive low molecular weight polyisobutylene was conducted by the use of benzoyl peroxide as an initiator through the solvothermal method. Fourier transform infrared spectra and ¹H‐NMR spectra confirmed that maleic anhydride was successfully grafted onto highly reactive low molecular weight polyisobutylene backbone, and the grafting mechanism also was proposed. The effect of benzoyl peroxide content, MAH concentration, total reactant amount in the reaction vessels, reaction temperature and time, and different kinds and volumes of solvents on MAH's degree of grafting was investigated in detail. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Styrene‐assisted grafting of maleic anhydride onto isotactic poly butene‐1

Grafting of maleic anhydride (MAH) onto isotactic poly butene‐1 (iPB‐1) was carried out by thermal decomposition of dicumyl peroxide (DCP) using electron‐donating monomer styrene (St), and were carried out in the molten state in a twin‐screw extruder according to an experimental design in which the content of MAH and St were varied. The calibration curve was constructed from FTIR measurements and titration which can obtain the absolute amounts of grafted MAH according to FTIR data. The proposed mechanism was that when St is added to the iPB‐1/MAH/peroxide grafting system, St reacted first with MAH to form a charge‐transfer complex (CTC). Then CTC react (or copolymerize) with macroradicals. The grafting of MAH onto iPB‐1 (iPB‐1‐MAH) accelerated crystalline transformation rate of form II to I. The contact angle decreased with the increase of grafting degree, which indicated that surface polarity increased. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Grafting copolymerization of maleic anhydride onto styrene‐butadiene‐styrene block copolymer through solvothermal process

The grafting copolymerization of maleic anhydride (MAH) onto styrene‐butadiene‐styrene terpolymer (SBS) was carried out through a new synthesis method––solvothermal synthesis. Infrared (IR) spectra and solid state ¹³C‐NMR confirmed that maleic anhydride was successfully grafted onto the SBS backbone. The effects of different solvents, different initiators and their concentration, the amount of MAH, SBS concentration, and reaction time on the graft degree were evaluated, and the optimal conditions were obtained. Results indicated that the grafting reaction of MAH onto SBS through solvothermal method can be carried out in both good solvents and poor solvents, which are much different from the traditional solution grafting method, and high grafting degree can be obtained in good solvents. Finally, we also compared the grafting degree (GD) prepared by the solvothermal method with that by the melt grafting method and solution grafting method. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5274–5279, 2006     

Structure and mechanism of functional isotactic polypropylene via in situ chlorination graft copolymerization

This paper discusses the structure and mechanism of maleic anhydride (MAH) grafted onto isotactic polypropylene (iPP) via in situ chlorination graft copolymerization (ISCGC). The molecular structure of the grafted iPP was characterized using ¹H NMR and ¹³C NMR spectroscopy, viscosity‐average molecular weight and gel content. The structure of un‐grafted MAH present in the reaction system was investigated using Fourier transform infrared spectroscopy in order to explore the grafting of MAH on iPP. The main side‐reactions, including iPP chain scission and crosslinking, during the grafting reaction were explored. From the experimental results obtained, the reason for controlled macromolecular chain degradation and crosslinking of grafted iPP in ISCGC is proposed. Based on the structural characterization of the grafted polymer, the mechanism of grafting onto iPP obtained via ISCGC was deduced. Mechanical properties, both static and dynamic, of grafted iPP were also investigated and the results showed that the properties of the material changed due to grafted MAH. Copyright © 2011 Society of Chemical Industry     

Effects of ABS‐g‐MAH on mechanical properties and compatibility of ABS/PC alloy

The effects of a compatibilizer, namely, an acrylonitrile–butadiene–styrene copolymer (ABS) grafted with maleic anhydrade (MAH) (ABS‐g‐MAH), on the mechanical properties and morphology of an ABS/polycarbonate (PC) alloy were studied The results showed that a small quantity of ABS‐g‐MAH has a very good influence on the notched Izod impact strength of the ABS/PC alloy without compromising other properties such as the tensile strength, flexural strength, and Vicat softening temperature (VST). The impact strength of the ABS/PC alloy, to a great extent, depends on the loading of ABS‐g‐MAH and the degree of grafting (DG) of MAH in the ABS‐g‐MAH. DSC analysis and SEM observation confirmed that ABS‐g‐MAH could significantly improve the compatibility of the ABS/PC alloy. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 831–836, 2001     

Solvothermal preparation of maleic anhydride grafted onto acrylonitrile-butadiene-styrene terpolymer (ABS)

The grafting copolymerization of maleic anhydride (MAH) onto acrylonitrile-butadiene-styrene terpolymer (ABS) was carried out through solvothermal process. Infrared (IR) spectra and ¹H NMR spectra confirmed that maleic anhydride was successfully grafted onto the ABS backbone. The influences, such as MAH concentration, the initiator's content, reaction temperature and time, comonomer, ABS concentration and different solvents, on the grafting copolymerization were also studied. Results indicated that the preparation of MAH grafted onto ABS through solvothermal method can be carried out in both good solvent and poor solvent, which is much different from the traditional solution grafting method, and high grafting degree can be obtained in good solvent.     

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。     

Modification of low‐density polyethylene by graft copolymerization with maleic anhydride and blends with polyamide 6

Modification of low‐density polyethylene (LDPE) hyperbranched grafting with a maleic anhydride (MAH) was carried out using corotating twin screw extruder in the presence of benzoyl peroxide. The LDPE/polyamide 6 (PA6) and LDPE‐g‐MAH/PA6 blends were obtained with a corotating twin screw extruder. The melt viscosity of the grafted LDPE was measured by a capillary rheometer. The grafted copolymer was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy The effects of variations in temperature, PA6 loading, and benzoyl peroxide and MAH concentration were investigated. The results show that most MAH monomers were grafted onto the LDPE at a lower MAH concentration. With the proper selection of the reaction parameters, we obtained a grafting degree higher than 4.9%. Mechanical test results indicate that the blends had good interfacial adhesion and good stability of the phase structure during heating, which was reflected in the mechanical properties. Furthermore, the results reveal that the tensile strength of the blends increased continuously with increasing PA6 content. Moreover, the home‐synthesized maleated LDPE could be used for the compatibilization of LDPE/PA 6 blends. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Parameters affecting the grafting reaction and side reactions involved in the free‐radical melt grafting of maleic anhydride onto high‐density polyethylene

The parameters affecting the grafting reaction and side reactions in free‐radical melt grafting of maleic anhydride (MA) onto high‐density polyethylene with the aid of 2,5‐dimethyl‐2,5‐di(t‐butyl peroxy)hexane peroxide(DTBPH) have been studied using an internal mixer. MA grafting degree of the maleated samples was measured with titrometry and FTIR spectroscopy methods. The extent of chain‐branching/crosslinking side reactions was evaluated with gel content and MFI determination. The flow behavior and melt viscoelastic properties of the samples were measured using a rheometric mechanical spectrometer. DTBPH and MA concentrations, reaction temperature, rotor speed, the type and concentration of coagents were among the studied parameters. The results show that MA and DTBPH concentration has a major role on the grafting reaction, chain‐branching/crosslinking side reactions and also the grafts microstructure in the final product. The reaction temperature has a complex effect on the maleation reaction. Increasing the rotor speed causes an increase in MA grafting degree of the samples and reduces the competitive side reactions. By using Gaylord additives, gel formation reduces at the expense of a dramatic decrease in the grafting degree. MA grafting degree is increased by the use of comonomers in the reaction and this is accompanied with a decrease in crosslinking side reaction when the vinyl type styrene comonomer is used. The results of processing torque in combination with the measurements of the melt viscoelastic property and gel content of the samples provide a great insight into understanding the gel formation mechanism. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

马来酸酐溶液法接枝改性天然橡胶的研究

采用溶液法，选用极性单体马来酸酐(MAH)，在非隔氧条件下，以过氧化苯甲酰(BPO)为引发剂对天然橡胶(NR)进行接枝改性。通过傅立叶红外光谱对接枝物进行定性表征；采用化学滴定法测定了反应产物的接枝率和接枝效率；详细讨论了反应单体和引发剂的用量、反应时间等因素对反应产物接枝率和接枝效率的影响；并应用正交设计法评价了各因素对产物接枝率和接枝效率的影响。     

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