Maleic Anhydride Groups Research Articles

Non-Isothermal Crystallization Behaviors of Ethylene Vinyl Acetate Copolymer and Ethylene Vinyl Acetate Copolymer-Graft-Maleic Anhydride

Maleic anhydride (MAH) was melt-grafted on ethylene-vinyl acetate copolymer (EVA) with a grafting degree of 6.3%. Through studying the crystal structure of the resulting EVA-g-MAH, the MAH groups had little influence on crystal structure. According to the Owaza model analysis of the non-isothermal crystallization kinetics of EVA-g-MAH and EVA, the MAH groups had a large blocking effect on crystallization. However, the Mo model showed that the crystallization rate of EVA-g-MAH was slightly faster than EVA. The crystallization activation energy was calculated by the Takhor and Kissinger models, and both results indicated that EVA had a larger effective energy barrier than EVA-g-MAH.

Effects of ENR and OMMT on barrier and tensile properties of LDPE nanocomposite film

The effects of organo-modified montmorillonite (OMMT) nanoclay and epoxidized natural rubber (ENR) content on the gas barrier, tensile, and the thermal properties of nanocomposite films based on low-density polyethylene (LDPE) are investigated. Linear low-density polyethylene-grafted maleic anhydride (LLDPE-g-MA) is used as a compatibilizer to obtain better dispersion of the nanoclay in the blends. The blends, with various amounts of ENR (0–10) wt%, are melt-compounded and extruded using a blown film extrusion single screw. The tensile properties of films are studied in machine direction (MD). The gas permeability of films is studied via constant pressure and a soap bubble flow meter. The melting and crystallization behaviors of films are examined via differential scanning calorimetry (DSC). Chemical interactions of composite blends are examined via Fourier transform infrared (FTIR) spectroscopy. An addition of 6 wt% nanoclay improved the tensile modulus by about 11 %. It further reduced the oxygen permeability by about 83 %. Although introducing OMMT decreased the percentage of crystallinity (XC), the presence of LLDPE-g-MA in the nanocomposite enhanced the property due to better intercalation between the phases. Incorporation of ENR caused an increase in the Young’s modulus for compatibilized nanocomposite systems, attributed to an interaction among clay, compatibilizer, and ENR, and cross-linking effects of ENR molecules. However, ENR decreased the permeability of the film due to the ability of amorphous regions to form crystallized structures during the blown process, and cross-linking effects of ENR. In addition, ENR reduced the XC of nanocomposites due to an interference that exists in the form of ENR molecular incorporation. The FTIR spectra showed that the maleic anhydride group in LLDPE-g-MA reacted in situ with the epoxy groups of ENR, which was an evidence of grafting reaction.

Effect of Graphene Nanosheets on the Morphology, Crystallinity, and Thermal and Electrical Properties of Super Tough Polyamide 6 Using SEBS Compounds

Super tough polyamide 6 was prepared by using SEBS and effect of SEBS-g-MA as a compatibilizer of PA6/SEBS matrix on mechanical properties was investigated. Thus super tough polyamide 6/graphene nanocomposites were produced using graphene nanosheets (GNs) through the melt compounding method. To compare the effectiveness of graphene, effects of graphite and carbon black (the other carbon structures) are also studied on the same matrix. The effects of graphene on crystallinity, improvements of morphology, and thermal and electrical properties of the nanocomposites were researched and compared with similar samples of graphite and carbon black. Due to the reaction between the maleic anhydride groups of SEBS and amine groups of nylon chains during the melt mixing process, super tough polyamide 6 was produced with high impact and tensile strength. The most important results of this study can be noted as an increase in the electrical conductivity and thermal stability by adding graphene to PA6/SEBS blend. Also the effect of graphene compatibility on PA6/SEBS/SEBS-g-MA blend was investigated with studying morphology.

On novel bio-hybrid system based on PLA and POSS

In this work, a novel strategy for the preparation of bio-hybrid systems based on polylactic acid (PLA) and polyhedral oligomeric silsesquioxane (POSS) was developed. Indeed, the new method consists in a preliminary functionalization of the polymer matrix and a subsequent reaction of silsesquioxane molecules, characterized by amino or hydroxyl functionalities, potentially capable of reacting with maleic anhydride groups created onto PLA by a free radical process. The method adopted to create maleic anhydride-grafted polylactic acid (PLA-g-MA) allowed to graft 0.7 wt% of MA onto the polymer backbone, avoiding a dramatic reduction of PLA molecular mass. 1H-NMR measurements demonstrated a different reactivity of the two used POSS, namely trans-cyclohexanediolisobutyl POSS (POSS-OH) and aminopropyl heptaisobutyl POSS (POSS-NH2). Indeed, the amino group of POSS-NH2 was found to react with the maleic anhydride group of PLA-g-MA allowing to obtain a hybrid system, carrying silsesquioxane molecules along the polymer backbone while the reactivity of POSS-OH turned out to be much lower. Thermal properties of the synthesized hybrid systems were assessed by means of DSC measurements. Indeed, the presence of POSS grafted onto the macromolecular chain was found to improve PLA crystallinity, by affecting the crystal nucleation density. Moreover, a decrease of surface water wettability was observed in the films made of PLA-g-MA/POSS-NH2.

Toughening mechanisms in interfacially modified HDPE/thermoplastic starch blends

The mechanical behavior of polymer blends containing 80wt% of HDPE and 20wt% of TPS and compatibilized with HDPE-g-MA grafted copolymer was investigated. Unmodified HDPE/TPS blends exhibit high fracture resistance, however, the interfacial modification of those blends by addition of HDPE-g-MA leads to a dramatic drop in fracture resistance. The compatibilization of HDPE/TPS blends increases the surface area of TPS particles by decreasing their size. It was postulated that the addition of HDPE-g-MA induces a reaction between maleic anhydride and hydroxyl groups of the glycerol leading to a decrease of the glycerol content in the TPS phase. This phenomenon increases the stiffness of the modified TPS particles and stiffer TPS particles leading to an important reduction in toughness and plastic deformation, as measured by the EWF method. It is shown that the main toughening mechanism in HDPE/TPS blends is shear-yielding. This article demonstrates that stiff, low diameter TPS particles reduce shear band formation and consequently decrease the resistance to crack propagation.

Preparation of functionalized graphene/SEBS-g-MAH nanocomposites and improvement of its electrical, mechanical properties

Graphene was first surface modified with octadecylamine to prevent the aggregation of graphene itself and also improve the compatibility between the graphene and polymer matrix. Then it was solution mixed with SEBS grafted with maleic anhydride (SEBS-g-MAH) to prepare graphene/SEBS-g-MAH nanocomposites. FTIR results show that esterification reaction took place by a “grafting to” method between maleic anhydride group of SEBS-g-MAH and the residual hydroxyl of graphene. Rheological data indicated that storage modulus increased sharply with 0.5wt% addition content of graphene, due to forming the network of graphene in SEBS-g-MAH. The tensile strength was enhanced by 69%, ranging from 1.94 to 3.28MPa. The alternating current conductivity at 1Hz of nanocomposites increased from 2.5 ×10−16 to 1.2×10−11S/cm, compared with that of SEBS-g-MAH. The above results were attributed to the good dispersion of graphene in SEBS-g-MAH matrix and interfacial chemical interaction between graphene and SEBS-g-MAH.

Thermoplastic Elastomer by Terpolymer Reactive Blending of Polyamide-6, Ethylene-1-Butene Rubber and Ethylene Ionomer

Reactive blending of polyamide-6 (PA6), maleic anhydride grafted ethylene-1-butene copolymer (EB-g-MAH) and ethylene-methacrylic acid ionomer partially neutralized by sodium ions (EMAA-Na) was performed to obtain a heat and oil resistant thermoplastic elastomer (TPE). The strain at break of the PA6/EB-g-MAH (40/60) was clearly higher than that of the PA6/EB (40/60). Addition of 2 wt% of EMAA-Na to the PA6/EB-g-MAH (38/60) blend induced an increase of the tensile modulus. TEM images confirmed that the PA6 was the matrix phase in the PA6/EB-g-MAH (40/60) blend, while the EB rubber phase was the matrix in the PA6/EB (40/60) blend. It was considered that the reaction between amino end groups of PA6 and maleic anhydride in EB-g-MAH induced the significant change of blend morphology. The PA6/EB-g-MAH/EMAA-Na blend showed similar morphology with the PA6/EB-g-MAH blend, and the EMAA-Na was expected to be located within the EB-g-MAH phase. It was found that ionic aggregates were formed in the EB-g-MAH phase by neutralization of the hydrated EB-g-MAH with sodium ions. The change of the mechanical properties by addition of EMAA-Na was due to the ionic aggregate formation which acted as physical crosslinks in the EB-g-MAH phase.

Design of a multi-dopamine-modified polymer ligand optimally suited for interfacing magnetic nanoparticles with biological systems.

We have designed a set of multifunctional and multicoordinating polymer ligands that are optimally suited for surface functionalizing iron oxide and potentially other magnetic nanoparticles (NPs) and promoting their integration into biological systems. The amphiphilic polymers are prepared by coupling (via nucleophilic addition) several amine-terminated dopamine anchoring groups, poly(ethylene glycol) moieties, and reactive groups onto a poly(isobutylene-alt-maleic anhydride) (PIMA) chain. This design greatly benefits from the highly efficient and reagent-free one-step reaction of maleic anhydride groups with amine-containing molecules. The availability of several dopamine groups in the same ligand greatly enhances the ligand affinity, via multiple coordination, to the magnetic NPs, while the hydrophilic and reactive groups promote colloidal stability in buffer media and allow subsequent conjugation with target biomolecules. Iron oxide nanoparticles ligand exchanged with these polymer ligands have a compact hydrodynamic size and exhibit enhanced long-term colloidal stability over the pH range of 4-12 and in the presence of excess electrolytes. Nanoparticles ligated with terminally reactive polymers have been easily coupled to target dyes and tested in live cell imaging with no measurable cytotoxicity. Finally, the resulting hydrophilic nanoparticles exhibit large and size-dependent r2 relaxivity values.

Localization of carbon nanotubes in polyamide 6 blends with non-reactive and reactive rubber

Blending of two immiscible polymer matrices can be an effective way to combine favourable properties of both blend partners. The additional incorporation of multiwalled carbon nanotubes (MWCNTs) in such thermoplastic blends may further enhance the blend properties and especially generate electrical conductivity.In the present study, 20 wt.% of non-reactive rubber and maleic anhydride functionalized rubber were melt blended with polyamide 6 and 3 wt.% MWCNTs by using different incorporation strategies. For the blends containing non-reactive rubber, the MWCNTs were always localized selectively in the thermodynamically preferred polyamide phase as shown by TEM images and electrical measurements. Interestingly, the different strategies resulted in different localization behaviours of the MWCNTs in case of the reactive rubber. These findings demonstrate the significant influence of maleic anhydride groups of the rubber component on localization of MWCNTs in the different blend phases which results in different values of electrical volume resistivity of the blends.

Transparent lithium-6 based polymer scintillation films containing a polymerizable fluor for neutron detection

A novel transparent polymer neutron scintillation material poly[styrene-co-lithium maleate-co-2-phenyl-5-(4-vinylphenyl)oxazole] has been synthesized and characterized for thermal neutron detection and neutron/gamma-ray discrimination. The terpolymer was synthesized using solution-based free radical polymerization and had a composition by mass of 60.64% styrene, 31.64% maleic anhydride, and 7.72% 2-phenyl-5-(4-vinylphenyl)oxazole. The maleic anhydride groups were hydrolyzed and titrated with 6LiOH to form the lithiated terpolymer, resulting in a 6Li content of 2.96% by mass. Monomer and polymer synthesis, film fabrication protocols, photoluminescence, and scintillation responses of this new scintillation material are reported. This approach demonstrates a novel method by which mechanically robust and transparent 6Li-based polymer films can be produced.

Cu(II), Zn(II) and Mn(II) complexes of poly(methyl vinyl ether-alt-maleic anhydride). Synthesis, characterization and thermodynamic parameters

The complexes of poly(methyl vinyl ether-alt-maleic anhydride) (poly(MVE-alt-MA)) with Zn(II), Mn(II) and Cu(II) ions were synthesized from the reaction of the aqueous solution of copolymer and metal(II) chlorides at different temperatures ranging from 25° to 40°C. Elemental analysis of the metal–polymer complexes suggests that the metal to ligand ratio is 1:1. The formation constants of each complex were determined by the mol-ratio method. UV–Vis studies showed that the complex formation tendency increased in the following order: Zn(II) > Cu(II) > Mn(II). This order was confirmed by the Irving–William series and Pearson’s classification. The IR spectral data indicated the metal ions to be coordinated through the hydroxyl groups of the hydrolysed maleic anhydride. The intrinsic viscosity and thermal properties of the copolymer and metal–polymer complexes and their thermal stability are discussed.

Encapsulated phase structure and morphology evolution during quiescent annealing in ternary polymer blends with PA6 as matrix

ABSTRACTThis work is aim to study the encapsulated morphology development in ternary blends of polyamide 6/high density polyethylene/maleic anhydride‐grafted‐ethylene propylene diene monomer (PA6/HDPE/EPDM‐g‐MA) and polyamide 6/maleic anhydride‐grafted‐high density polyethylene/ethylene propylene diene monomer (PA6/HDPE‐g‐MA/EPDM) through thermodynamically control described by Harkins spreading theory. The phase morphology was confirmed by using scanning electron microscope (SEM) and selective solvent extraction revealed that PA6/HDPE/EPDM‐g‐MA blend having a composition of 70/15/15 vol % is constituted of polyamide 6 matrix with dispersed composite droplets of HDPE subinclusions encapsulated by EPDM‐g‐MA phase, while for PA6/HDPE‐g‐MA/EPDM blend with the same composition is constituted of polyamide 6 matrix with dispersed composite droplets of HDPE‐g‐MA subinclusions encapsulated by EPDM phase. Quiescent annealing test revealed that for PA6/HDPE/EPDM‐g‐MA blend, a perfect core–shell structure with one HDPE particle encapsulated by EPDM‐g‐MA phase was formed during annealing, and for PA6/HDPE‐g‐MA/EPDM blend, a novel complete inverting HDPE‐g‐MA/EPDM core/shell structure was achieved. Moreover, quantitative analysis about coalescent behaviors of HDPE‐g‐MA and HDPE subinclusions during quiescent annealing were investigated by image analysis and the result suggested that the grafted maleic anhydride group in HDPE‐g‐MA, acted as a role of steric repulsion, could suppress coalescence effects, thus leaded to a lower coalescent rate than that of HDPE subinclusions. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39937.

Adhesion of maleic anhydride functionalized polyolefins and blends

ABSTRACTWe study three new classes of olefin‐based polymer, low‐molecular‐weight homopolypropylene (LMW‐hPP), syndiotactic‐rich polypropylene (srPP), and random propylene polymer (RPP). RPP is a random propylene/ethylene copolymer. By blending LMW‐hPP with 20 wt % of a maleic anhydride (MA) functionalized srPP (MA‐srPP) or MA functionalized RPP (MA‐RPP) instead of a commercial MA‐iPP (maleic anhydride‐grafted‐isotactic polypropylene), adhesion to a polar substrate, such as polyester (Mylar), is greatly enhanced. Effects of crystallinity controlled by either stereoregularity or comonomer incorporation and molecular weight of these MA functionalized propylene‐based polymers on adhesive performance are discussed. To further understand the mechanisms of enhanced adhesion, Sum Frequency Generation (SFG) spectroscopy is used to evaluate the migration of MA‐srPP in LMW‐hPP towards the interface when contacting a polar sapphire substrate. It shows that the buried interface between the LMW‐hPP/MA‐srPP blend (wt ratio = 80/20) and sapphire has the same characteristic spectrum as the MA‐srPP/sapphire interface, suggesting the enrichment of MA‐srPP in the interfacial polymer when the blend is in contact with sapphire. Also, vibrational modes of C=O have been detected at both the blend/sapphire and MA‐srPP/sapphire interfaces, further indicating that the interfacial polymer contains MA groups. Besides Mylar, adhesion to the non‐polar iPP substrate is also studied. The adhesion mechanisms to these polar and non‐polar substrates are explained in terms of our adhesion model. Applications of these MA functionalized polyolefins and blends are envisioned in the tie‐layer and adhesive areas. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39855.

Preparation of Waterborne Epoxy Resin Emulsion

The hydrophilic carboxylic group was induced into the main chain of the bisphenol-A-type epoxy resin via alcoholysis reaction between the maleic anhydride and he secondary hydroxyl group of the bisphenol-A-type epoxy resin. Then a self-emulsifying type aqueous epoxy resin was developed. The chemical structure of the resultant was analyzed by FT-IR. The effects of temperature, time, ratio of reactants and neutralization temperature on the reaction were discussed. Then the optimum reaction condition was determined through orthogonal experiment design. The synthesized waterborne epoxy resin has favorable stability and water-dispersion.

Tensile, rheological properties, thermal stability, and morphology of ethylene vinyl acetate copolymer/silica nanocomposites using EVA-g-maleic anhydride

In this article, we present a study on the properties of ethylene vinyl acetate copolymer/silica nanocomposites prepared in absence and presence of EVA-g-maleic anhydride as a compatibilizer between silica nanoparticles and ethylene vinyl acetate matrix. A series of ethylene vinyl acetate/silica nanocomposites with different contents of silica nanoparticles were prepared by solution method. EVA-g-maleic anhydride with 0.5 wt% maleic anhydride groups was added to all ethylene vinyl acetate/silica nanocomposites. Fourier transform infrared, field emission scanning electron microscopy, rheology behavior, and thermogravimetry analysis were used to characterize the structure, morphology, rheological, and thermal properties of the nanocomposites, respectively. The Fourier transform infrared spectra and field emission scanning electron microscopy micrographs showed that the hydroxyl groups on the surface of silica nanoparticles interact with maleic anhydride groups in EVA-g-maleic anhydride and lead to a finer dispersion of individual silica nanoparticles in the ethylene vinyl acetate matrix. The rheological properties and thermal stability of ethylene vinyl acetate/silica nanocomposites were significantly increased after adding EVA-g-maleic anhydride into the nanocomposites. Mechanical properties including tensile strength and elongation at break of the nanocomposites were mainly affected by the content of silica nanoparticles. For the tensile strength as well as elongation at break of the nanocomposites, a maximum value was observed at the content of 0.5 wt% of silica nanoparticles. The addition of EVA-g-maleic anhydride into ethylene vinyl acetate/silica nanocomposites resulted in a further improvement of mechanical properties of the nanocomposites.

A facile method to prepare high-performance magnetic and fluorescent bifunctional nanocomposites and their preliminary application in biomolecule detection.

Magnetic and fluorescent bifunctional nanocomposites have great potential in biomolecule detection and biological imaging applications. So far, it remains a challenge to prepare bifunctional nanocomposites with high colloidal and fluorescent stability. To address this problem, we utilized a simple ring-opening reaction to conjugate Fe3O4 and CdZnSeS quantum dots (QDs). The surface amine groups of SiO2-coated Fe3O4 nanoparticles (Fe3O4@SiO2) opened the rings of the surface maleic anhydride groups of poly(styrene-co-maleic anhydride)-coated CdZnSeS QDs (QDs@PSMA), and then the resulting nanocomposite was functionalized with Jeffamine M-1000 polyetheramine (JMP) by a ring-opening reaction. The structures and properties of the bifunctional nanocomposites were fully characterized by transmission electron microscopy, dynamic light scattering, spectrofluorometry and vibrating sample magnetometry. The results indicated that the nanocomposites prepared by the conjugation method had dramatically higher quantum yields (QYs) than those prepared by the SiO2 co-encapsulation method. After introducing JMP, the nanocomposites exhibited high fluorescent and colloidal stability over a wide pH range (pH 2-13), a low level of protein adsorption in PBS with 10% fetal bovine serum at 37 °C, and a negligible level of nonspecific binding when incubated with HeLa cells. Sandwich fluoroimmunoassay results indicated that the nanocomposites can be successfully applied in a variety of diagnosis and bioimaging applications.

Preparation and characterization of poly(lactic acid)/starch composites toughened with epoxidized soybean oil

Blends of entirely bio-sourced polymers, namely polylactide (PLA) and starch, have been melt-compounded by lab-scale co-extruder with epoxidized soybean oil (ESO) as a reactive compatibilizer. The starch granules were grafted with the maleic anhydride (MA) to enhance its reactivity with ESO. The ready reactions between the epoxy groups on ESO, the MA groups on MA-grafted starch (MGST) and the end carboxylic acid groups of PLA brought blending components together and formed a compatible compound. An elongation at break (EB) of 140% was obtained in the blend of PLA/MGST/ESO (80/10/10), increased from 5% of a pure PLA. The grafting content of the MA on the starch granules primarily determined the compatibility and properties of the ternary blends, which was also affected by the relative amount of MGST and ESO.

Dynamic rheology and morphology of HDPE‐fumed silica composites: Effect of interface modification

AbstractIn the present study, high density polyethylene (HDPE)‐based composites containing different amounts of fumed silica (FS) were prepared by melt compounding in a corotating twin screw extruder. Polyethylene‐g‐maleic anhydride copolymer (PE‐g‐MA) containing 1 wt% maleic anhydride was used for interface modification between filler and polymer. The interaction between the surface hydroxyl groups of fumed silica nanoparticles with maleic anhydride groups of PE‐g‐MA led to a finer dispersion of the filler in the HDPE matrix. The terminal complex viscosity and terminal storage modulus were highest at 1 wt% filler loading due to widely spread network formation by FS nanoparticles. This filler network plausibly got disturbed at higher filler content and/or interface modification which was reflected in their stress relaxation behavior also. The dynamic rheological behavior of the composites was explained in terms of morphological observations. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers

Melt-neutralization of maleic anhydride grafted on high-density polyethylene compatibilizer for polyamide-6/high-density polyethylene blend: effect of neutralization level on compatibility of the blend

Blends of polyamide-6 (PA-6) and high-density polyethylene (HDPE) with blend ratios of 80/20 (wt/wt) and 20/80 (wt/wt) were studied using zinc-neutralized maleic anhydride (MAH) grafted HDPE as compatibilizers. MAH groups were hydrolyzed and neutralized with different amounts of zinc acetate dihydrate in a twin-screw extruder to produce different levels of zinc-neutralization (0, 14, 41, 69, and 95 %) at one and ten parts per hundred of resin of compatibilizer. Melt neutralization of MAH was confirmed by X-ray fluorescence, FT–IR, and rheological properties. SEM micrographs showed a large reduction in the dispersed phase size in the compatibilized blends. Tensile measurements showed improvement of tensile strength for all compatibilized blends; moreover, the elongation at break of compatibilized blends at 10 phr of compatibilizer was improved. Blending increased the crystallization temperature for the PA-6, and the addition of compatibilizer reduced the crystallization temperature slightly. A significant increase in melt viscosity of the compatibilizer was found with zinc addition and adding compatibilizer increased the viscosity of the blends. However, the addition of zinc to the compatibilizer did not change the viscosity in the PA-6-rich blends and actually led to a decrease in viscosity in the HDPE-rich blends.

Epoxidized natural rubber–toughened polypropylene/organically modified montmorillonite nanocomposites

The objective of this study is to toughen organically modified montmorillonite (OMMT)-filled polypropylene (PP) nanocomposites with epoxidized natural rubber (ENR). PP, ENR (10–20 wt%), OMMT (6 wt%) and maleated PP (PP-g-MA; 10 wt%) were melt blended using counterrotating twin extruder, followed by injection molding to prepare test samples. X-ray diffraction results revealed that the OMMT platelets in PP/OMMT nanocomposites were intercalated and the incorporation of ENR into the nanocomposites further increased the d-spacing of OMMT layers. The Fourier transform infrared spectra showed that the maleic anhydride group in PP-g-MA reacted in situ with the epoxy groups of ENR, which demonstrates the occurrence of grafting reaction. With slight decrease in stiffness and strength, the addition of 20 wt% ENR increased the impact strength of PP/ENR/OMMT nanocomposites by 521% compared to PP/OMMT nanocomposites. Scanning electron microscopy images revealed that the ENR particle size increased with increasing ENR contents in PP/ENR/OMMT nanocomposites. Differential scanning calorimetry results revealed that the presence of ENR and OMMT had slightly increased the crystallization temperature as well as the degree of crystallinity of PP. Thermogravimetric analysis showed that the blending of ENR decreased the thermal stability of PP/OMMT nanocomposites.