Grafting Of Maleic Anhydride Research Articles

Replacing Harmful Flame Retardants with Biodegradable Starch-Based Materials in Polyethylene Formulations.

The addition of toxic flame retardants to commercially available polymers is often required for safety reasons due to the high flammability of these materials. In this work, the preparation and incorporation of efficient biodegradable starch-based flame retardants into a low-density polyethylene (LDPE) matrix was investigated. Thermoplastic starch was first obtained by plasticizing starch with glycerol/water or glycerol/water/choline phytate to obtain TPS-G and TPS-G-CPA, respectively. Various LDPE/TPS blends were prepared by means of melt blending using polyethylene graft maleic anhydride as a compatibilizer and by varying the content of TPS and a halogenated commercial flame retardant. By replacing 38% and 76% of the harmful commercial flame retardant with safe TPS-G-CPA and TPS-G, respectively, blends with promising fire behavior were obtained, while the limiting oxygen index (LOI ≈ 28%) remained the same. The presence of choline phytate improved both the charring ability and fire retardancy of starch and resulted in a 43% reduction in fire growth index compared to the blend with commercial flame retardant only, as confirmed by means of cone calorimetry. Standard UL 94 vertical tests showed that blends containing TPS exhibited dripping behavior (rated V2), while those with commercial flame retardant were rated V0. Overall, this work demonstrates the potential of starch as a natural flame retardant that could reduce the cost and increase the safety of polymer-based materials.

Combined Effect of Poly(lactic acid)-Grafted Maleic Anhydride Compatibilizer and Halloysite Nanotubes on Morphology and Properties of Polylactide/Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) Blends.

Given the global challenge of plastic pollution, the development of new bioplastics to replace conventional polymers has become a priority. It is therefore essential to achieve a balance in the performances of biopolymers in order to improve their commercial availability. In this topic, this study aims to investigate the morphology and properties of poly(lactic acid) (PLA)/ poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) (at a ratio of 75/25 (w/w)) blends reinforced with halloysite nanotubes (HNTs) and compatibilized with poly(lactic acid)-grafted maleic anhydride (PLA-g-MA). HNTs and PLA-g-MA were added to the polymer blend at 5 and 10 wt.%, respectively, and everything was processed via melt compounding. A scanning electron microscopy (SEM) analysis shows that HNTs are preferentially localized in PHBHHx nodules rather than in the PLA matrix due to its higher wettability. When HNTs are combined with PLA-g-MA, a finer and a more homogeneous morphology is observed, resulting in a reduction in the size of PHBHHx nodules. The presence of HNTs in the polymer blend improves the impact strength from 12.7 to 20.9 kJ/mm2. Further, with the addition of PLA-g-MA to PLA/PHBHHX/HNT nanocomposites, the tensile strength, elongation at break, and impact strength all improve significantly, rising from roughly 42 MPa, 14.5%, and 20.9 kJ/mm2 to nearly 46 MPa, 18.2%, and 31.2 kJ/mm2, respectively. This is consistent with the data obtained via dynamic mechanical analysis (DMA). The thermal stability of the compatibilized blend reinforced with HNTs is also improved compared to the non-compatibilized one. Overall, this study highlights the effectiveness of combining HNTs and PLA-g-AM for the properties enhancement of PLA/PHBHHx blends.

Toward the Improvement of Maleic Anhydride Functionalization in Polyhydroxybutyrate (PHB): Effect of Styrene Monomer and Sn(Oct)2 Catalyst.

In this work, polyhydroxybutyrate (PHB) was maleic anhydride (MA)-grafted in the molten state, using dicumyl peroxide (DCP) as a reaction initiator. Tin(II) 2-ethylhexanoate (Sn(Oct)2) and styrene monomer (St.) were used to maximize the maleic anhydride grafting degree. When PHB was modified with MA/DCP and MA/DCP/Sn(Oct)2, viscosity was reduced, suggesting chain scission in relation to pure PHB. However, when the styrene monomer was added, the viscosity increased due to multiple grafts of MA and styrene into the PHB chain. In addition, the FTIR showed the formation of a new band at 1780 cm-1 and 704 cm-1, suggesting a multiphase copolymer PHB-g-(St-co-MA). The PHB (MA/DCP) system showed a grafting degree of 0.23%; however, the value increased to 0.39% with incorporating Sn(Oct)2. The highest grafting efficiency was for the PHB (MA/DCP/St.) system with a value of 0.91%, while the PHB (MA/DCP/St./Sn(Oct)2) hybrid mixture was reduced to 0.73%. The chemical modification process of PHB with maleic anhydride increased the thermal stability by about 20 °C compared with pure PHB. The incorporation of 0.5 phr of the Sn(Oct)2 catalyst increased the efficiency of the grafting degree in the PHB. However, the St./Sn(Oct)2 hybrid mixture caused a deleterious effect on the maleic anhydride grafting degree.

An automated algorithm for the determination of oil absorption strategy of magnetic nanoparticles from SEM images

In recent years, the magnetic iron oxide nanoparticles (MNPs) are employed as efficient absorbents for oil removal from water. In this research, the particle size (diameter) obtained from Scanning Electron Microscopy (SEM) images of MNPs, before and after oil-absorption, are utilized to determine the oil-absorption capacity. However, the manual evaluation of the particle size and particle size distribution (PSD) are highly time-consuming and needs expertised people for accurate analysis. Hence, an image processing algorithm is employed for the determination of particle size and PSD from the Scanning Electron Microscopy (SEM) images. The key objective revolves with the preparation of the Maleic Anhydride Grafted Polypropylene anchored Magnetic Nanoparticles (MAPP-a-MNPs) to absorb crude oil from the marine water. The shape, size, and size distribution of MAPP-a-MNPs were assessed by both manual and automated analysis. For this purpose, expertise people help with the manual analysis and Threshold Adaptive-Canny Edge Detection (TA-CED) and Accumulator Updated-Circular Hough Transform (AU-CHT) method is employed for automated analysis. All the automated process were conducted in MATLAB and the measurements were taken for both before and after the oil absorption images. These measurements aid us to determine the quantity of oil absorbed by MAPP-a-MNPs. The results demonstrates excellent oil removal capacity of MAPP-a-MNPs.

A Comprehensive Monte Carlo Model of the Grafting of Maleic Anhydride onto Polypropylene with Experimental Validation

AbstractA Monte Carlo model is employed to investigate the grafting of maleic anhydride onto polypropylene using a peroxide initiator. The study aimed to develop a comprehensive model that considered a very detailed kinetic mechanism, including chain transfer to polymer, homopolymerization as well as several copolymer reactions. The relative importance of these reactions is evaluated using a sensitivity analysis, which identified homopolymerization, β‐scission, chain grafting, and termination by disproportionation as the most influential reactions. The kinetic constants of these reactions are tuned to fit reported experimental data using the Surface Response Method. The model considers a pseudo‐homogeneous reaction medium and predicts average molecular weights, degree of grafting, molecular weight distribution, and grafting distribution. Furthermore, model simulations provided useful information about the impact of initial concentrations of reactants and reaction time on the molecular properties of the grafted polymer.

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.

Evaluating the grafting of Maleic anhydride with Poly(lactic acid) (PLA) and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) via batch compounding

Maleic anhydride (MA) was grafted to Poly(lactic acid) (PLA) and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) at twelve different content ratios by batch compounding method. The rheology, morphology and grafting possibilities of blend components were analysed. It was found that excessive peroxide content can cause chain scission and chain shortening in the blend which produces a porous structure with inferior mechanical properties. The addition of MA increases the degradation rate of the blend. MA increased the dispersity and interfacial adhesion of PHBV phase within PLA phase.

The effects of surface modified date‐palm fiber fillers upon the thermo‐physical performances of high density polyethylene‐polyvinyl chloride blend with maleic anhydride as a grafting agent

AbstractTo demonstrate the upcycling of thermoplastic waste with good thermo‐physical properties, high density polyethylene (HDPE; 80 phr) and polyvinyl chloride (PVC; 20 phr) are mixed as the matrix using maleic anhydride (MAH) reinforced with unmodified and modified date palm fibers (DPFs; 30 phr). The effects of in situ grafting of MAH onto the DPFs‐HDPE‐PVC composites upon the resultant thermo‐physical characteristics are investigated and analyzed via Fourier transform infrared spectroscopy and scanning electron microscopy. Thus, the effective compatibilizing of both the HDPE‐PVC component and the grafted HDPE‐PVC blend with the modified DPFs are confirmed. In addition, the results of dynamical mechanical analysis and differential scanning calorimetry indicate that the glass transition temperature (Tg) of the composite is enhanced by the incorporation of modified DPFs. The thermal, mechanical, and water uptake properties of the composites are also improved. Rheological analysis at low frequency reveals that the introduction of hydrolyzed DPFs results in a higher complex viscosity (1.94 × 106 Pa s) and storage modulus (119,844 MPa) for the obtained composite (designated G‐Hydro). Overall, the G‐Hydro composite exhibits the best performance, making it ideal for a variety of construction and building purposes.

Blending of Low-Density Polyethylene and Poly(Butylene Succinate) (LDPE/PBS) with Polyethylene-Graft-Maleic Anhydride (PE-g-MA) as a Compatibilizer on the Phase Morphology, Mechanical and Thermal Properties.

It is of significant concern that the buildup of non-biodegradable plastic waste in the environment may result in long-term issues with the environment, the economy and waste management. In this study, low-density polyethylene (LDPE) was compounded with different contents of poly(butylene succinate) (PBS) at 10-50 wt.%, to evaluate the potential of replacing commercial plastics with a biodegradable renewable polymer, PBS for packaging applications. The morphological, mechanical and thermal properties of the LDPE/PBS blends were examined in relation to the effect of polyethylene-graft-maleic anhydride (PE-g-MA) as a compatibilizer. LDPE/PBS/PE-g-MA blends were fabricated via the melt blending method using an internal mixer and then were compression molded into test samples. The presence of LDPE, PBS and PE-g-MA individually in the matrix for each blend presented physical interaction between the constituents, as shown by Fourier-transform infrared spectroscopy (FTIR). The morphology of LDPE/PBS/PE-g-MA blends showed improved compatibility and homogeneity between the LDPE matrix and PBS phase. Compatibilized LDPE/PBS blends showed an improvement in the tensile strength, with 5 phr of compatibilizer providing the optimal content. The thermal stability of LDPE/PBS blends decreased with higher PBS content and the thermal stability of compatibilized blends was higher in contrast to the uncompatibilized blends. Therefore, our research demonstrated that the partial substitution of LDPE with a biodegradable PBS and the incorporation of the PE-g-MA compatibilizer could develop an innovative blend with improved structural, mechanical and thermal properties.

Controlled functionalization of polypropylene by VETEMPO-mediated radical chemistry

New chemistry for grafting maleic anhydride (MAn) and N-aryl maleimides to a propylene homopolymer is described. Whereas conventional peroxide-initiated maleations are accompanied by extensive degradation, formulations containing a small amount of 4-vinyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl (VETEMPO) can meet graft content targets while minimizing melt viscosity losses. The first stage of a VETEMPO-mediated process involves alkyl radical trapping by nitroxyl to yield polymer-bound alkoxyamines bearing pendant vinyl ether functionality. Subsequently, copolymerization between vinyl ether and MAn builds polymer molecular weight while offsetting the degradation incurred by the standard MAn grafting mechanism. The result is a lightly branched, maleated product with a melt viscosity close to that of the starting material. This VETEMPO-based copolymerization strategy is adapted to generate thermoset PP derivatives by peroxide-initiated reactions of VETEMPO with an appropriate difunctional monomer such as N,N′-1,3-phenylene dimaleimide (PDM).

Study on modified poplar wood powder/polylactic acid high toughness green 3D printing composites

In order to alleviate environmental pollution and the shortage of petroleum resources, improve the utilization of renewable materials, the research of biodegradable green composite materials has become a research hotspot. In this paper, Poplar Wood powder(PWP) and Polylactic acid(PLA) were selected, adding poly lactic acid graft maleic anhydride (MPLA) and Silane coupling agent KH-550 (KH550) as a compatibilizer and coupling agent to improve interface compatibility, at the same time, poly Butylenedioate-co-terephthalate (PBAT) and poly Butylene Succinate (PBS) were added to improve the toughness of the composites. The experimental results show that, the impact strength of 20 %-KMPP/PBAT/PBS composite modified by MPLA and KH550 was 20.70 kJ/m−2. Secondly, the hydrophobic angle of the composite material is as high as 112°. It is found that the high content of PWP with small particle size (200 mesh) can make it more evenly dispersed in the composite material, and the cross section of the composite material was smooth. The modified composite was 4.24$/kg, which reduced the cost by 28.07 %. The research results have opened up a new way to develop 3D printed biomass composites with low cost, high compatibility, high toughness and good environmental adaptability, and broadened the application scope and value of the composites.

Removal of oils and organic solvents from wastewater through swelling of porous crosslinked poly(ethylene-co-vinyl acetate): Preparation of adsorbent and their oil removal efficiency

In this novel study, an attempt has been made to prepare porous crosslinked poly(ethylene-co-vinyl acetate) polymer (C-EVA). The porous C-EVA was prepared by grafting of maleic anhydride and cetyl alcohol onto the polymer backbone with addition of NaCl as porogen in the brabender mixture at 120 °C and 80 rpm. This was followed by leaching of NaCl with water extraction to generate a highly porous polymer structure which was evident from its SEM micrographs. The polymer was found to have excellent swelling capacity in various oils and organic solvents and showed good selective absorption capacity. The reusability of the synthesized polymer was studied and it was found that it could be reused for more than 30 absorption desorption cycles without undergoing much change in its absorption capacity. The cross-linked polymeric composite was further characterized by FTIR, TGA, XRD, and SEM.

Grafting of maleic anhydride on poly(lactic acid)/hydroxyapatite composites augments their ability to support osteogenic differentiation of human mesenchymal stem cells.

Implantation of bone substitutes is the treatment of choice for bone defects exceeding a critical size, when self-healing becomes impossible. The use of 3D printing techniques allows the construction of scaffolds with customized properties. However, there is a lack of suitable materials for bone replacement. In this study, maleic anhydride-grafted poly (lactic acid) (MAPLA) was investigated as a potential compatibilizer agent for 3D-printed polylactic acid (PLA)/hydroxyapatite (HA) composites, in order to enhance the physicochemical and biological properties of the scaffolds. The grafting process was performed by reactive processing in a torque rheometer, with the evaluation of the use of different concentrations of maleic anhydride (MA). The success of the grafting reaction was confirmed by titration of acid groups and spectroscopic analyses, indicating the presence of succinic anhydride groups on the PLA chain. Morphological analysis of the PLA/HA 3D scaffolds, using SEM, revealed that the use of the compatibilizer resulted in a structure free from voids and holes. The compatibilization also increased the degradation process. On the other hand, TGA and DSC analyses revealed that the use of a compatibilizer had little effect on the thermal properties of the composite. Most importantly, the samples with compatibilizer were demonstrated to have a minimal cytotoxic effect on human mesenchymal stem cells (MSCs), promoting the osteogenic differentiation of these cells in a medium without the addition of classical osteogenic factors. Therefore, the grafting of PLA/HA composites improved their physicochemical and biological properties, especially the induction of MSC osteogenic differentiation, demonstrating the potential of these scaffolds for bone tissue replacement.

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.

Graphene-maleic anhydride-grafted-carboxylated acrylonitrile butadiene-rubber nanocomposites

Ethylene-propylene grafted-maleic anhydride (EPR-g-MA) and a pure maleic anhydride (MA) were separately used to compound carboxylated acrylonitrile butadiene-rubber (XNBR) together with reduced graphene oxide (G) to form nanocomposites, by using melt compounding technique. The G-sheets in the presence of MA (GA samples) or EPR-g-MA (GB samples) generally increased the physico-mechanical properties including; crosslinking density, tensile strength and thermal degradation resistance etc., when compared with sample without MA or EPR-g-MA (GAO) and the virgin matrix. For the thermal degradation resistance measured by the char residue (%), by using thermal gravimetric analysis technique; GA1 (0.1 ph G and 0.5 ph MA) was 106.4% > XNBR and 58% > GAO (0.1 ph G) while that of GB1 (0.1 ph G and 0.5 ph EPR-g-MA) was 60% > XNBR and 22.2% > GAO respectively. Although, homogeneous dispersions of the G-sheets assisted by MA or EPR-g-MA was a factor, but the strong bonding (covalent, hydrogen and physical entanglements) occurring in GA and GB was observed to be the main contributing factor for these property enhancements. Thus, these nanostructured materials have exhibited multifunctional capabilities and could be used for advanced applications including high temperature (heat sinks), flame retardants, and structural applications.

Research and production of antimicrobial polymer blends from thermoplastic and polyguanidine

Microorganisms are one of the main causes of food spoilage and diseases that seriously affect human health. Therefore, the development of materials with antibacterial ability to help repel diseases and epidemics, improve the quality of life and, in particular, ensure food safety and hygiene is receiving much attention. In this study, first, PE wax was selected as the resin matrix for grafting maleic anhydride (MAH) to obtain PEw-g-MAH. Then, PEw-g-MAH continued to be used as the frame for Polyhexamethylene guanidine (PHMG) grafting; the obtained material was PEw-g-PHMG. Finally, PEw-g-PHMG was mixed with LLDPE resin to make antimicrobial polymer blend materials and applied to produce antibacterial films used in preserving agricultural products. The mixing ratio amongst materials was investigated to attain suitable properties. The results determined the proportions of materials suitable for MAH and Styrene were 8 and 12%, PHMG and PEw-g-PHMG were 45 and 7%, respectively. At these ratios, the resulting polymer blend has mechanical and antimicrobial properties suitable for applying film packaging and food preservation.

Removal of organic solvents and oils from wastewater by absorption with crosslinked poly (ethylene-co-vinyl acetate) modified by cetyl alcohol

In this first investigation on the oil absorption capacity of poly (ethylene-co-vinyl acetate), a novel crosslinked poly (ethylene-co-vinyl acetate) (EVA) based absorbent was prepared by the grafting of maleic anhydride (MA) and cetyl alcohol (CA) in the presence of benzoyl peroxide (BP). Although EVA has been widely used in various applications like drug delivery, encapsulation, and footwear industry, however, its application in environmental remediation has not been studied in detail. In this study, melt mixing was carried out in the Brabender mixture at 120 °C. The grafted polymer was post-cured in the hot air oven at 100 °C for 24 h. The post-cured sorbent showed excellent absorption capacity in toluene (2200 %), gasoline (1720 %), crude oil (1105 %), and kerosene (390 %). The contact angle measurement reveals its hydrophobic nature (123°). The absorption properties of this hydrophobic composite remain stable even after 10 absorption/desorption cycles with absorption capacity remaining constant. The crosslinked polymer was characterized by FTIR, XRD, TGA, and SEM.

Characterization of Biodegradable Composites from Polypropylene, Polypropylene Grafted Maleic Anhydride, and Durian Seed Starch

The characterization of biodegradable composite from durian seed starch that is mixed polypropylene, and polypropylene grafted maleic anhydride has been done. The stages of this preparation were, the first had prepared durian seed starch, the second had the process of grafting maleic anhydride into polypropylene and the third had made of composite with the composition of PP:PP-g-MA: DSS (7:0.5:0.2); (7:0.5:0.3); (7:0.5:0.4); (7:0.5:0.5); (7:0.5:0.6) (w/w). The biodegradable composites obtained were characterized by tensile strength, surface morphology analysis by SEM, differential thermal analysis (DTA), analysis in nature with the ability to decompose biodegradable test, and functional groups analysis by FTIR spectroscopy. The results showed that the biodegradable composites have the best properties in the ratio of PP:PP-g-MA: DSS was (7:0.5:0.5) (w/w) with the test results of tensile stress is 12.556 N/m2, and the elongation is 8.600%, the images on a few flat surfaces and improved homogeneity, temperature change, and strong group interactions as well as having good biodegradable properties.

Fabrication of Biodegraded Composite from Polypropylene, Polypropylene Grafted Maleic Anhydride, and Chempedak Seed (Artocarpus integer) Starch

Fabrication of biodegraded composite from polypropylene, polypropylene grafted maleic anhydride, and chempedak seed (Artocarpus integer) starch has been conducted. The stages were prepared starch of Cempedak seed, grafting process of maleic anhydride on polypropylene, and fabrication of composite with a composition ratio of PP: PP-g-MA: starch of chempedak seed (9.5:0.5:0.1)g, (9.5:0.5:0.2)g, (9.5:0.5:0.3)g, (9.5:0.5:0.4)g, (9.5:0.5:0.5) g, and PP: starch of chempedak seed (10:2)g. The composites obtained were characterized using tensile strength and elongation testing, surface morphology analysis by SEM, analysis in nature with the ability to decompose by biodegradable test, and functional groups analysis by FTIR spectroscopy. The results showed that the biodegradable composites have the best properties in the ratio of PP: PP-g-MA: starch of chempedak seed (9.5:0.5:0.1)g with the test results of tensile strength was 28.743 N/m2, and also the SEM results show that flat surface and improved homogeneity, and strong group interactions as well as having good biodegradable properties.