Melt Grafting Of Maleic Anhydride Research Articles

Super Tough PA6/PP/ABS/SEBS Blends Compatibilized by a Combination of Multi-Phase Compatibilizers.

Development of multi-component blends to prepare high-performance polymer materials is still challenging, and is a key technology for mechanical recycling of waste plastics. However, a multi-phase compatibilizer is prerequisite to create high-performance multi-component blends. In this study, POE-g-(MAH-co-St) and SEBS-g-(MAH-co-St) compatibilizers are prepared via melt-grafting of maleic anhydride (MAH) and styrene (St) dual monomers to polyolefin elastomer (POE) and poly [styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS), respectively. Subsequently, these compatibilizers are utilized to compatibilize the PA6/PP/ABS/SEBS quaternary blends through melt-blending. When POE-g-(MAH-co-St) and SEBS-g-(MAH-co-St) are added, respectively, both can promote the distribution of the dispersed phases, significantly reducing the dispersed phase size. When adding 10 wt% POE-g-(MAH-co-St) and 10 wt% SEBS-g-(MAH-co-St) together, compared to the non-compatibilized blend, the fracture strength, fracture elongation, and impact strength surprisingly increased by 106%, 593%, and 823%, respectively. It can be attributed to the hierarchical interfacial interactions which facilitate gradual energy dissipation from weak to strong interfaces, resulting in the improvement of mechanical properties. The synergistic effect of the enhanced phase interfacial interactions and toughening effect of elastomer compatibilizer achieved simultaneous growth in strength and toughness.

Functionalization of Low-Molecular-Weight Polyethylene by Melt Grafting of Maleic Anhydride for Using as a Compatibilizer

In this study, functionalization of low-molecular-weight polyethylene by melt grafting of maleic anhydride was investigated. The results reveal that initiator concentration, reaction time and temperature have the greatest influence on the graft degree. Structure of maleic anhydride grafted low-molecular-weight po-lyethylene was proven by FTIR, DTA and XRD me-thods. The grafted low-molecular-weight polyethylene has a potential application as a compatibilizer for mate-rials based on polyethylene compounds.

Water as a medium for microwave-assisted grafting of maleic anhydride onto a polypropylene film to improve its adhesion with a polyamide 6 film

Maleic anhydride (MAH)-modified polypropylene (PP), denoted as PP-g-MAH, is often prepared by melt grafting of MAH onto PP through reactive extrusion. A major problem of this process is the presence of a large amount of residual (unreacted) MAH in the polymer, which is harmful for applications like food packaging. This work aims to study microwave-assisted grafting of MAH onto PP film surfaces using water instead of organic solvents as a medium to reduce MAH residues in PP. Microwave irradiation shortens the grafting time by accelerating the decomposition of initiator. Addition of a very small amount (2%) of xylene to water swells the PP film surfaces of about 12 μm thick to which the MAH grafting is confined. The adhesive strength of a double layer film based on PP-g-MAH (moisture barrier layer) and polyamide 6 (PA6, oxygen barrier layer) reaches 13.3 N/15 mm instead of 2.4 N/15 mm for that based on PP and PA6. A much less amount of the oil-soluble benzoyl peroxide is more efficient as an initiator for MAH grafting than water-soluble ammonium persulfate.

Enhancing the interfacial bond strength of aluminum/polymer laminated film of the soft package lithium‐ion battery through polydopamine surface modification

AbstractThe aluminum (Al) foil used in Al/polymer laminated film of the soft package lithium‐ion battery (LIB) is widely treated with a hexavalent chromate conversion coating to increase the adhesive strength and durability of the adhesive joint. Given that hexavalent chromate is toxic and carcinogenic, a novel and chromate‐free method was developed in this study for surface modification of the Al foil using polydopamine (PDA) functionalization after titanium (Ti) chemical conversion. Ti conversion favors the deposition of PDA and introduces more functional groups of PDA on the Al surface. A novel polypropylene‐based hot melt adhesive, MAH‐g‐(PP/PBE), was prepared by melt grafting of maleic anhydride on the blend of polypropylene and propylene‐based elastomer for use as the inner adhesive of Al/polymer laminated film. Then, treated Al foil/MAH‐g‐(PP/PBE) composites were prepared and their interfacial adhesive strengths were investigated. The results show that the amine and catechol groups of PDA improve the interfacial adhesion between adhesive and Al foil by improving the wettability and interfacial interaction. The peel strength between MAH‐g‐(PP/PBE) and PDA functionalized Al foil after Ti conversion treatment can reach 3.55 N/mm, which is increased by 322% compared with that between MAH‐g‐PP and untreated Al foil. PDA functionalization after Ti chemical conversion and MAH‐g‐(PP/PBE) have great potential to improve interfacial adhesion of Al/polymer laminated film used in LIB package.

Enhanced impact strength of compatibilized poly(lactic acid)/polyamide 11 blends by a crosslinking agent

AbstractMaleated poly(lactic acid) (PLA‐g‐MA) was prepared through melt grafting of maleic anhydride onto a PLA backbone with the aid of a radical initiator. PLA‐g‐MA thus formed was incorporated into PLA/polyamide 11 (PA11) blends as a reactive compatibilizer. By morphological observation, it was assessed that PLA‐g‐MA lowered the interfacial energy and strengthened the interface between PLA and PA11. However, the compatibilized PLA/PA11 blends did not show significant improvement of impact strength compared with noncompatibilized PLA/PA11 blends. Measurements of the molecular weight and impact strength of PLAs compounded with various amounts of radical initiators revealed that decreased molecular weight of PLA by the radical initiator used for the preparation of PLA‐g‐MA is responsible for this unexpected result. To compensate the decrease of the molecular weight, a crosslinking agent was incorporated in the preparation step of PLA‐g‐MA. It was found that the crosslinking agent is effective in preventing the molecular weight reduction. As a result, the impact strength of the PLA/PA11 blend was enhanced to a great extent by the PLA‐g‐MA prepared with the crosslinking agent.

Effect of co-monomer on the adhesive performance of PP-g-MAH between cast polypropylene film and aluminum foil

Three functionalized polypropylenes (PPs) were successfully prepared for use as the inner adhesive layer of aluminum/polymer laminated film by melt grafting of maleic anhydride (MAH) on PP with styrene (St), diallyl phthalate (DAP) and triallyl isocyanurate (TAIC) as co-monomers, respectively. The effects of these co-monomers (St, DAP and TAIC) on the grafting degree of MAH, gel content, thermal property and adhesive performance of MAH grafted PP (PP-g-MAH) were investigated. The results show that the T-peeling and heat-sealing strengths of TAIC-assisted PP-g-MAH (PP-g-MAH/TAIC) are 28.6 and 70.4 N /15 mm, which are increased by 33.6% and 20.8% compared to DAP-assisted PP-g-MAH (PP-g-MAH/DAP), and by 142.4% and 81.0% compared to St-assisted PP-g-MAH (PP-g-MAH/St), respectively. The grafting degree of MAH reaches a maximum of 2.3 wt% in PP-g-MAH/TAIC, which leads to a higher crystallization temperature than PP-g-MAH/DAP and PP-g-MAH/St. PP-g-MAH/TAIC also has better thermal stability than the other two functionalized PPs, as TAIC can effectively reduce PP chain scission and promote the formation of a cross-linked structure during the melt grafting.

Acyloxyimide derivatives as efficient promoters of polyolefin C–H functionalization: application in the melt grafting of maleic anhydride onto polyethylene

Acyloxyimides as a new H-abstracting agent have been developed for the radical grafting of maleic anhydride (MA) onto polyethylene in the melt state.

FUNCTIONALIZATION OF EPDM RUBBER TOWARD BETTER SILICA DISPERSION AND REINFORCEMENT

ABSTRACTFunctionalization of non-polar ethylene propylene diene monomer (EPDM) rubber by melt grafting of maleic anhydride (MA) and in situ incorporation of sol–gel derived silica in the MA grafted EPDM has been done to prepare EPDM/silica composites to use dual benefits of both the approaches, which results in adequate rubber–filler compatibility, good filler dispersion, and enhanced composite properties. Controlled growth of silica up to 25 parts per hundred rubber (phr) is carried out with the solution sol–gel process using tetraethoxysilane (TEOS) as a silica precursor. Mechanical and dynamical properties of the composites are found to improve consistently as silica content increases. Furthermore, treatment of maleic anhydride grafted EPDM by γ-aminopropyltrimethoxysilane (γ-APS) results in remarkable improvement in composite properties even at the same silica content. This is attributed to the generation of uniformly dispersed spherically shaped nanosilica throughout the rubber matrix as observed in a transmission electron microscopic (TEM) study. This contributes to enhanced crosslinking density and improved rubber–filler interaction. In fact, the reinforcement effect brought by in situ silica relative to unmodified in situ silica/EPDM composites is found to be much higher than that reported in recent work on EPDM/in situ silica composites even with higher silica loading. The mechanical, rheological, and dynamic mechanical behaviors of all the composites are evaluated and compared in detail.

Montmorillonite as support for peroxide in the melt grafting of maleic anhydride onto polypropylene

ABSTRACTGrafting of maleic anhydride onto polypropylene was performed in a Haake torque rheometer, in the presence of organically modified montmorillonite, MMT (used as support for the peroxide), according to a 23 factorial design, where the maleic anhydride concentration (CMA), peroxide concentration (Cper) and reaction time (tr) were varied. For comparison, the reaction in the absence of MMT was also conducted. Polypropylene degradation was assessed by parallel plate rheometry and size exclusion chromatography (SEC) and percentage of reacted maleic anhydride (%MAg) was obtained by titration and FTIR spectroscopy. The results showed differences in both systems, conventional and in the presence of MMT. The structure of polypropylene grafted with maleic anhydride, PP‐g‐MA, indicates longer branches are formed in the presence of MMT compared to in its absence, demonstrated by FTIR analysis. As in conventional reaction systems, an increase in Cper caused an increase in %MAg and a reduction in molar mass. The variable CMA showed to be not significant in the grafting reaction in the presence of MMT, even at high DCP levels, at a 5% significance level. On the other hand, increase in CMA resulted in significant increase in viscosity. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44134.

The effect of epoxy and tetramethyl thiuram disulfide on melt‐grafting of maleic anhydride onto polypropylene by reactive extrusion

ABSTRACTIn this report, melt grafting of maleic anhydride (MAH) and epoxy resin onto polypropylene (PP) by peroxide‐initiated reactive extrusion has been investigated. As evidenced by Fourier transform infrared spectroscopy, both MAH and epoxy resin were successfully grafted onto PP through the reactions of MAH with PP and epoxy resin with MAH. It was found that tetramethyl thiuram disulfide could promote the grafting of MAH and inhibit the degradation of PP, as revealed by chemical titration and melt flow experiments, through prolonging the lifetime of the macroradical; meanwhile, epoxy resin could reduce the sublimation of MAH and the maximum grafting degree of MAH. Furthermore, the introduction of grafted products was found to enhance the mechanical properties of PP/glass fiber composites, and this influence was very significant at high grafting degrees with a high content of epoxy resin, which could be interpreted in terms of improved compatibility and adhesion at the interface. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43422.

Functionalisation of ethylene–propylene copolymer by melt grafting of maleic anhydride using a high shear internal mixer

This study focused on synthesising a peroxide-initiated maleic anhydride-g-ethylene–propylene copolymer via melt grafting using a Haake internal mixer at high shear rate. The effect of maleic anhydride and dicumyl peroxide percentage on the grafting efficiency of maleic anhydride onto ethylene–propylene copolymer chains was carried out through a two-level factorial experimental design using Design Expert 6.0.5 software. The maleic anhydride and dicumyl peroxide content were varied, in the range of 1–5 and 0·1–0·3 phr, respectively. The grafting parameters were fixed at a temperature of 180°C and rotor speed of 60 rev min−1 for 5 minutes. The grafting efficiency was determined by Fourier transform infrared spectroscopy analysis based on cumulative absorbance of anhydrides’ characteristic peaks and supported by differential scanning calorimetry and field emission scanning electron microscopy analyses. The grafting was highly influenced by maleic anhydride and dicumyl peroxide content. The optimum functionalisation was achieved at 5 phr maleic anhydride and 0·3 phr peroxide addition.

Study on Melt Grafting of MAH onto P(3HB-co-4HB)/PLA Blends

The melt grafting of maleic anhydride (MAH) onto poly (3-hydroxybutyrate-co-4-hydrox-ybutyrate)[P(3HB-co-4HB)]/polylactic acid (PLA) blends were carried out via reactive extrusion. The effects of the contents of MAH, initiator (BPO) on the graft ratio were studied. The effects of grafting modification on thermal properties, mechanical properties, fracture morphology and compatibility of P(3HB-co-4HB)/PLA blends were characterized by differential scanning calorimeter (DSC), electronic universal testing machine and scanning electron microscopy (SEM) etc. The results showed that the graft ratio of blends increased to a maximum and then decreased with increasing contents of MAH and BPO; The tensile strength, impact strength of blends were significantly improved, and the graft ratio achieved the maximum value at 1.0phr MAH and 0.3phr BPO; Through analysis from DSC and SEM, it indicated that the compatibility of P(3HB-co-4HB)/PLA blends was improved effectively.

Melt grafting of maleic anhydride onto polypropylene with assistance of α‐methylstyrene

AbstractMelt grafting of maleic anhydride (MA) and α‐methylstyrene (AMS) onto polypropylene (PP) was performed by reactive extrusion. Effects of AMS on the graft degree of MA, crystallization behavior, and thermal properties of the graft copolymer were investigated. Results show that the addition of AMS as a comonomer can efficiently improve the MA graft degree. When the molar ratio of AMS to MA is 0.9:1, the maximum MA graft degree is attained, which increases about 56% compared with that using single monomer of MA. The results of the graft degree of MA obtained by chemical titration (CT) agree well with those obtained by Fourier transform infrared spectroscopy (FTIR). Melt flow rate (MFR) measurements indicate that the addition of AMS effectively reduces the degradation of PP molecules. The wide‐angle X‐ray diffraction (WAXD) results show that in comparison with the PP‐g‐MA sample, the PP‐g‐(MA‐AMS) sample shows no new crystalline form, but has a slight decrease in the average crystalline domain size. According to the results of thermogravimetry (TG) and differential scanning calorimetry (DSC), the graft PP in the presence of AMS exhibits a lower melting point and a higher crystallization temperature and thermal stability in comparison with that without AMS. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers

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

AbstractThe 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

A study on melt grafting of maleic anhydride onto low‐density polyethylene and its blend with polyamide 6

AbstractGraft copolymerization of low‐density polyethylene (LDPE) with a maleic anhydride (MAH) was performed using intermeshing corotating twin‐screw extruder in the presence of benzoyl peroxide (BPO). The LDPE/polyamide 6 (PA6) and LDPE‐g‐MAH/PA6 blends were prepared in 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 (FTIR) and scanning electron microcopy (SEM). The influence of the variation in temperature, BPO and MAH concentration, and temperature on the grafting degree and on the melt viscosity was studied. The grafting degree increased appreciably up to about 0.45 phr and then decreased continuously with an increasing BPO concentration. According to the FTIR analysis, it was found that the amount of grafted MAH on the LDPE chains was ∼5.1%. Thermal analysis showed that melting temperature of the graft copolymers decreases with increasing grafting degree. In addition to this, loss modulus (E″) of the copolymers first increased little with increasing grafting and then obviously decreased with increasing grafting degree. Furthermore, the results revealed that the tensile strength of the blends increased linearly with increasing PA6 content. The results of SEM and mechanical test showed that the blends have good interfacial adhesion and good stability of the phase structure, which is reflected in the mechanical properties. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 267–275, 2010

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

AbstractThe 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

Neodymium oxide co-catalyzed melt free radical grafting of maleic anhydride onto co-polypropylene by reactive extrusion

Rare earth oxide, neodymium oxide (Nd2O3), CO-catalyzed melt grafting of maleic anhydride (MAH) onto co-polypropylene (co-PP) in the presence of dicumyl peroxide (DCP) was carried out by reactive extrusion. The experimental results reveal that the addition of Nd2O3 as a coagent leads to an enhancement in both MFR and the grafting degree of MAH, along with a simultaneous decrease in the gel content. When the Nd2O3 concentration is 6.0 mmol%, the increment of the grafting degree of MAH maximally is up to about 20% compared with the related system without adding Nd2O3, and the gel content decreases simultaneously to a very low level of about 3%. Attenuated total reflection FTIR (ATR-FTIR) indicates that the gel in the graft copolymers mainly arise from the cross-linking reaction between ethylene units of co-PP. A reasonable reaction mechanism has been put forward on the basis of our experimental results and other mechanisms reported in the literature. We also tentatively explain above results by means of synergistic effect between DCP and Nd2O3, which causes a higher concentration of the macroradical, in particular the tertiary macroradical.

Parameters affecting the free‐radical melt grafting of maleic anhydride onto linear low‐density polyethylene in an internal mixer

AbstractOur main objective of this study was to study the parameters affecting the free‐radical melt grafting of maleic anhydride (MA) onto linear low‐density polyethylene (LLDPE) with dicumyl peroxide (DCP) in an internal mixer. The degree of grafting (DG) was measured with titrometry and Fourier transform infrared spectroscopy. The extent of chain‐branching/crosslinking was evaluated with gel content and melt flow index measurements. The flow behavior and melt viscoelastic properties of the grafted samples were measured by using rheometric mechanical spectrometry. Feeding order, DCP and MA concentration, reaction temperature, rotor speed, and grade of LLDPE were among parameters studied. The results show that the reactant concentration (MA and DCP) played a major role in the determination of the grafting yield and the extent of the chain‐branching/crosslinking as competitive side reactions. The order of feeding also had an appreciable effect on the DG and the side reactions. Increasing the rotor speed increased the grafting yield and reduced side reactions by means of intensification of the mixing of reactants into the polyethylene (PE) melt. Chain‐branching dominated the side reactions for lower molecular weight PE, whereas for higher molecular weight PE, chain‐branching led to crosslinking and gel formation. The results of the melt viscoelastic measurements on the grafted samples provided great insight into the understanding of the role of influential parameters on the extent of side reactions and resulting changes in the molecular structure of the grafted samples. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 141–149, 2006

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

AbstractMelt 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.

Melt grafting of maleic anhydride onto an ethylene–propylene–diene terpolymer (EPDM)

Peroxide-initiated melt grafting of maleic anhydride (MAH) onto an ethylene–propylene–diene terpolymer (EPDM) of high ethylene content (=74 wt%) has been studied using a Brabender Plasticoder. The grafting efficiency and crosslinking degree (gel content) of the grafted EPDM rubber (EPDM-g-MAH) were determined by FTIR spectroscopy and xylene extraction, respectively. It was established that both grafting and crosslinking reactions are mostly influenced by the dosage of the MAH and peroxide (2,5-dimethyl-2,5-di-( t-butylperoxy)hexane), respectively. The targeted relative high MAH grafting at low gel content was reached at low concentrations of both MAH (<5 wt%) and peroxide (<0.2 wt%). Processing variables, as mixing temperature and time, rotor speed and filling grade of the mixing chamber, showed only a marginal effect on the competing grafting and crosslinking reactions.