Maleic Anhydride Groups Research Articles

Enhancement of thermoelectric and mechanical properties of thermoplastic vulcanizates (TPVs) with hydroxylated graphene by dynamic vulcanization

Abstract In order to obtain higher thermoelectric and mechanical properties in nonpolar thermoplastic vulcanizates (TPVs), the butyl rubber/polypropylene (TPVs)/hydroxylated graphene (HGE) composites with nanosheet network were prepared through masterbatch technique and based on thermodynamic calculations, using polypropylene-graft-maleic anhydride (PP-MA) as a compatibilizer. The Fourier transform infrared (FTIR) and Raman spectra revealed the introduced maleic anhydride group on PP-MA can form strong interfacial interaction with hydroxyl-containing functional groups on HGE. Morphology study indicated the rubber particles in the composites occupied the most volume of the PP phase, as expected to hinder the aggregation of HGE and form the effective nanosheet network. The nanosheet network can be combined with the butyl rubber (IIR) cross-linked particles during the dynamic vulcanization process to improve the interface bonding between PP and IIR, thus increasing the tensile strength of TPVs. The prepared TPVs/HGE composites have significantly improved in mechanical properties, thermal properties and dielectric properties, which provides a guarantee for their potential application as multifunctional TPVs polymers.

Sericin cocoon bio-compatibilizer for reactive blending of thermoplastic cassava starch

Cassava starch was blended with glycerol to prepare thermoplastic starch (TPS). Thermoplastic starch was premixed with sericin (TPSS) by solution mixing and then melt-blended with polyethylene grafted maleic anhydride (PEMAH). The effect of sericin on the mechanical properties, morphology, thermal properties, rheology, and reaction mechanism was investigated. The tensile strength and elongation at break of the TPSS10/PEMAH blend were improved to 12.2 MPa and 100.4%, respectively. The TPS/PEMAH morphology presented polyethylene grafted maleic anhydride particles (2 μm) dispersed in the thermoplastic starch matrix, which decreased in size to approximately 200 nm when 5% sericin was used. The melting temperature of polyethylene grafted maleic anhydride (121 °C) decreased to 111 °C because of the small crystal size of the polyethylene grafted maleic anhydride phase. The viscosity of TPS/PEMAH increased with increasing sericin content because of the chain extension. Fourier-transform infrared spectroscopy confirmed the reaction between the amino groups of sericin and the maleic anhydride groups of polyethylene grafted maleic anhydride. This reaction reduced the interfacial tension between thermoplastic starch and polyethylene grafted maleic anhydride, which improved the compatibility, mechanical properties, and morphology of the blend.

Peroxide-Induced Synthesis of Maleic Anhydride-Grafted Poly(butylene succinate) and Its Compatibilizing Effect on Poly(butylene succinate)/Pistachio Shell Flour Composites.

Framing the Circular Bioeconomy, the use of reactive compatibilizers was applied in order to increase the interfacial adhesion and, hence, the physical properties and applications of green composites based on biopolymers and food waste derived lignocellulosic fillers. In this study, poly(butylene succinate) grafted with maleic anhydride (PBS-g-MAH) was successfully synthetized by a reactive melt-mixing process using poly(butylene succinate) (PBS) and maleic anhydride (MAH) that was induced with dicumyl peroxide (DCP) as a radical initiator and based on the formation of macroradicals derived from the hydrogen abstraction of the biopolymer backbone. Then, PBS-g-MAH was used as reactive compatibilizer for PBS filled with different contents of pistachio shell flour (PSF) during melt extrusion. As confirmed by Fourier transform infrared (FTIR), PBS-g-MAH acted as a bridge between the two composite phases since it was readily soluble in PBS and could successfully form new esters by reaction of its multiple MAH groups with the hydroxyl (–OH) groups present in cellulose or lignin of PSF and the end ones in PBS. The resultant compatibilized green composites were, thereafter, shaped by injection molding into 4-mm thick pieces with a wood-like color. Results showed significant increases in the mechanical and thermomechanical rigidity and hardness, meanwhile variations on the thermal stability were negligible. The enhancement observed was related to the good dispersion and the improved filler-matrix interfacial interactions achieved by PBS-g-MAH and also to the PSF nucleating effect that increased the PBS’s crystallinity. Furthermore, water uptake of the pieces progressively increased as a function of the filler content, whereas the disintegration in controlled compost soil was limited due to their large thickness.

Barrier performance and biodegradability of antibacterial poly(butylene adipate-co-terephthalate) nanocomposites reinforced with a new MWCNT-ZnO nanomaterial

A new nanomaterial or nano-filler in the form of multiwalled carbon nanotube-zinc oxide (MWCNT-ZnO) was synthesized for the purpose of modifying poly(butylene adipate-co-terephthalate) (PBAT) and its derivative (modified PBAT or MPBAT) through a melt-blending method (MPBAT was obtained by introducing maleic anhydride groups into PBAT). The effect of the new nano-filler on the properties of resultant nanocomposites was determined from the characterization of mechanical properties, morphology, crystallinity, thermal stability, barrier properties, hydrophilicity, conductivity, antibacterial property, and biodegradability. The results showed that MPBAT nanocomposites had stronger mechanical properties, better barrier properties, and higher electrical conductivity than PBAT nanocomposites. Scanning electron microscopy illustrated that MWCNT-ZnO had better compatibility with MPBAT than with PBAT. At 0.2% MWCNT-ZnO, the MPBAT/MWCNT-ZnO nanocomposite film exhibited the greatest mechanical properties (17.74% increase in tensile strength, 22.17% in yield strength, and 14.29% in elongation at break). When the MWCNT-ZnO content was 0.4%, the nanocomposite film demonstrated the best water vapor barrier ability (an increase of 30.4%). The MPBAT/MWCNT-ZnO film with 0.6% MWCNT-ZnO turned out to have the best oxygen barrier performance (an increase of 130% relative to pure PBAT). It was shown from the results of antibacterial evaluation that the new nanomaterial could impart PBAT and MPBAT with antibacterial activity. The biodegradability tests indicated that an MWCNT-ZnO content of 0.2% could slightly reduce the biodegradability, and when the content was higher than 0.2%, the weight loss rate would increase.

Improved Toughness of Polylactide by Binary Blends with Polycarbonate with Glycidyl and Maleic Anhydride‐Based Compatibilizers

AbstractThis work reports on the development of polylactide (PLA) and polycarbonate (PC) blends with different compatibilizers with enhanced toughness. Since both polymers are immiscible, two types of compatibilizers are tested: petrochemical‐based copolymers Xibond 160 and Xibond 920 with maleic anhydride and epoxy groups, respectively, and natural‐based compatibilizers with the same functionalities, namely maleinized linseed oil (MLO) and, epoxidized linseed oil (ELO). Mechanical, thermal, and morphological characterization shows better properties for the PLA/PC (80/20 wt%) blends with chemically modified natural oils (ELO and MLO). The addition of 5 phr (parts per hundred resin) of MLO gives the maximum values for impact strength and elongation at break. Moreover, the glass transition temperature (Tg) slightly decreases with the addition of natural compatibilizers, thus showing some plasticization effect. Petroleum‐derived compatibilizers give interesting results regarding tensile strength and stiffness without plasticization. PLA/PC blends show higher thermal stability than neat PLA, regardless of the compatibilizer used, since PC is much more thermally stable than PLA. The obtained results indicate that both petroleum‐based and natural‐derived compatibilizers positively contribute to enhance the properties of the binary PLA/PC blends. Nevertheless, the results with MLO suggest this is an interesting biobased solution to provide increased toughness to PLA/PC blends.

Grafting the carboxyl groups onto DPNR by seeded emulsion polymerization to enhance the compatibility with silica filler

The modification of deproteinized natural rubber (DPNR) with maleic anhydride (MAH) was synthesized to enhance the better compatibility between silica filler and natural rubber (NR). The presence of carboxylic acid groups (-COOH) of MAH after hydrolysis in the grafted DPNR with MAH (DP-g-MAH) would directly interact with the hydroxyl groups (-OH) of silica filler, resulting from the formation of the ester bonds due to the esterification reaction. It is leading to form the chemical bonding, which is the significantly strong interaction between DPNR and silica filler. The structural characterization of DP-g-MAH was analyzed by Fourier transform infrared spectrometer (FTIR) and proton nuclear magnetic resonance (1H-NMR), respectively. The % grafting level of MAH approximately highs to 99.37 % with the low gel content approximate 14.45 (wt%). In addition, the DP-g-MAH latex was compounded with silica nanofiller 10 phr by latex compounding method. The morphology of silica filled DP-g-MAH (DP-g-MAH/Si 10) was characterized by field-emission scanning electron microscope (FE-SEM) in order to observe the silica dispersion into the DP-g-MAH rubber. The FE-SEM shows that silica filler could disperse in grafted rubber more than the DPNR. In addition, the crosslink density was investigated to confirm the chemical networks, which could occur from esterification between DP-g-MAH and silica filler.

ACID-LABILE CORE CROSS-LINKED MICELLES FOR pH-TRIGGERED RELEASE OF DOXORUBICIN

A acid-labile core cross-linked micelle system of amphiphilic triblock copolymer of poly(oligo(ethylene glycol) methyl ether methacrylate)-block-poly(styrene-alt-maleic anhydride)-block-poly(styrene) (POEGMA-b-PSMA-b-PS) was prepared. The POEGMA-b-PSMA-b-PS triblock copolymers were synthesized by the reversible addition-fragmentation chain transfer (RAFT) polymerization. Doxorubincin (DOX) was entrapped into micellar structure with POEGMA block as a shell and PSMA-b-PS block as a core. Then, core cross-linking was carried out by amidation reaction between 2,2-bis(aminoethoxy)propane and maleic anhydride group inner core. DOX loading content and efficiency were calculated to be 18 and 90 (wt. %), respectively. Core cross-linked micelles illustrated good stability under physiological condition but disassociated rapidly under acidic pH. The DOX release experiments indicated a rapid DOX release at pH 5.0 compared to pH 7.4.

Effect of ion-crosslinking on supercritical CO2 foaming behavior and foam properties of EVA/ZnO composites

How to realize the recycling of materials is an important topic for polymer materials, especially crosslinked polymers. In this work, by means of the reaction of zinc oxide (ZnO) and maleic anhydride group, ethylene-vinyl acetate copolymer (EVA)/ZnO composites with reversible ion-crosslinking structure were prepared by melt mixing method. The gel content and the degree of ion crosslinking in EVA were tracked using the THF extraction method. The presence of ion-crosslinking structure strongly affected the foaming behavior of EVA composites in supercritical CO2 (sc-CO2) molding foaming process. The influence of the ion crosslinking on the structure and properties of EVA foams was studied by means of SEM and compression set test etc. The results showed that the appropriate degree of ion-crosslinking was beneficial to increase the volume expansion rate and cell density of the obtained foams, and reduce the average cell diameter and compression set of the foams. The obtained EVA composite foams showed good resilience and melt-reprocessing performance. However, too high ion-crosslinking degree severely limited the growth of cells due to the difficulty of molecular chain movement. At the same time, the excessive ZnO in the matrix had an adverse effect on the compression set of EVA foam.

Study of the Properties of Polyethylene/Thermoplastic Starch Blends: Determination of the Critical Compatibilizer Concentration

The use of immiscible polymers blends is highly prevalent worldwide in view of their unique properties. Nevertheless, the main technical obstacle in the way of developing novel polymers blends remains the effective compatibilization between their components. In this work, reactive compatibilization blends consisting of thermoplastic corn starch/low density polyethylene (TPCS)/LDPE and thermoplastic corn starch/linear low density polyethylene (TPCS)/LLDPE with different portions of polyethylene-grafted-maleic anhydride (PE-g-MA) as compatibilizer were prepared. The novelty of this study is that commercial PE and starches from the local market were used to determine the critical concentration of PE-g-MA needed to attain the best blend properties. FTIR study proved that in the blends containing 7% of compatibilizer, all the available maleic anhydride groups in the PE-g-MA had reacted with the hydroxyl groups of the starch forming new ester bonds. The MFI measurements showed that when the compatibilizer was added, the melt flow index of the blend decreases down to 7% of PE-g-MA and when more compatibilizer was added no more change in MFI was noticed because of the cessation of ester bonds forming. The thermal stability improved with the increase of (PE-g-MA) concentration till 7% then it decreased again at 9%. The elongation at break and the tensile strength reached the highest value with 7 wt % of PE-g-MA.

The Localization Behavior of Different CNTs in PC/SAN Blends Containing a Reactive Component.

Co-continuous blend systems of polycarbonate (PC), poly(styrene-co-acrylonitrile) (SAN), commercial non-functionalized multi-walled carbon nanotubes (MWCNTs) or various types of commercial and laboratory functionalized single-walled carbon nanotubes (SWCNTs), and a reactive component (RC, N-phenylmaleimide styrene maleic anhydride copolymer) were melt compounded in one step in a microcompounder. The blend system is immiscible, while the RC is miscible with SAN and contains maleic anhydride groups that have the potential to reactively couple with functional groups on the surface of the nanotubes. The influence of the RC on the localization of MWCNTs and SWCNTs (0.5 wt.%) was investigated by transmission electron microscopy (TEM) and energy-filtered TEM. In PC/SAN blends without RC, MWCNTs are localized in the PC component. In contrast, in PC/SAN-RC, the MWCNTs localize in the SAN-RC component, depending on the RC concentration. By adjusting the MWCNT/RC ratio, the localization of the MWCNTs can be tuned. The SWCNTs behave differently compared to the MWCNTs in PC/SAN-RC blends and their localization occurs either only in the PC or in both blend components, depending on the type of the SWCNTs. CNT defect concentration and surface functionalities seem to be responsible for the localization differences.

Effect of compatibilizers on lignin/bio-polyamide blend carbon precursor filament properties and their potential for thermostabilisation and carbonisation

Biobased blends from hydroxypropyl modified lignin (TcC) and a biobased polyamide (PA1010) were produced by continuous sub-pilot scale melt spinning process. A reactive compatibilization was employed with the help of two different compatibilizers (ethylene-acrylic ester-maleic anhydride (MA) and ethylene-methyl acrylate-glycidyl methacrylate (GMA)) to enhance the compatibility between the TcC and PA1010. The enhanced compatibility between the TcC and PA1010 achieved by reaction between hydroxyl groups with maleic anhydride groups in the MA compatibilizer or epoxy groups in the GMA compatibilizer via nucleophilic substitution, was confirmed by chemical (Fourier infrared measurements), physical (glass transition, melting and crystallization behaviour), rheological, morphological and tensile properties of the filaments from compatibilized blends. MA compatibilizer required a higher concentration (2 phr) than GMA (1 phr) to achieve an optimal performance because of the difference in the reactive group's concentration within the each compatibilizer. The MA compatibilizer though was more effective than GMA. The precursor blended filaments were successfully carbonized in a lab scale experiment to yield coherent carbon fibres with tensile stress values of 192 ± 77 and 159 ± 95 MPa; and moduli of 16.2 and 13.9 GPa respectively for uncompatibilised and 2% MA compatibilized blends. That the compatibilized carbon fibre properties are slightly inferior may be attributed to the need to accurately control and optimise applied stress during the thermostabilisation and carbonization stages. Notwithstanding, these differences, the results indicate the potential benefit of using compatibilized TcC/PA1010 blend filaments as carbon fibre precursors.

Study of the Moisture Mitigation and Toughening Effect of Fly‐ash Particles on Sisal Fiber‐Reinforced Hybrid Polypropylene Composites

This study focused on developing fly-ash and sisal fiber reinforced hybrid polypropylene (PP) composites. The hybridized composite containing 15 wt.% each of sisal fiber and fly-ash shows highest impact strength of 1.42 kJ/m2, demonstrating an improvement by ~ 125 % and ~ 25 % respectively in comparison to neat PP and composite reinforced with only sisal fiber. Highest and lowest tensile strengths of 37.09 MPa and 24.69 MPa were recorded by composite containing 30 wt.% each of sisal fiber and fly ash with PP and impact modified PP respectively. Flexural strength recorded a greatest value of 44.09 MPa for 30 wt.% reinforced sisal fiber with PP against a lowest estimate of 30.86 MPa for 30 wt.% reinforced fly ash with impact modified PP. The FTIR results confirmed the esterification reaction among sisal fibers and maleic anhydride groups. DMA showed an apparent positive shift in the glass transition temperatures of hybrid composites upon the addition of fly ash. Composite reinforced with 30 wt.% sisal fiber and fly ash exhibited a storage modulus of 13,155 MPa and 8,795 MPa at −80 oC, respectively. Thermal degradation stability of all the hybrid composites improved significantly. The lowest water uptake properties have been demonstrated from the composite with highest fly ash content (15 %).

Remarkable Role of Experimental Olefin-Maleic-Anhydride Copolymer Based Compatibilizing Additives in Blends of Waste PET Bottles and Polyamide

Over the past 50 years demand for plastics drastically increased worldwide resulting in plastic wastes causing serious environmental problems. The main market sector of European plastics industry is the packaging industry most of which are polyolefins and poly(ethylene-terephtalate). In the EU, 29.1 million tonnes of plastic waste were collected in 2018, of which 32.5% was recycled, 42.6% was recovered for energy, and 24.9% was landfilled (Plastics-the Facts, 2019). Although landfilling of collected waste in the EU is steadily declining, there is still too much unused waste. Polymer blends based on waste resources can solve the issues of recycling. The main purpose of the research was to produce polymer blends from waste based PET that have appropriate mechanical properties and rheological behaviour as well in order to find application areas where product requirements are not strict. Blends containing waste based PET were extrusion moulded and calenderd producing extrusion strings and films. Rheological and tensile properties of three types of PET/engineering thermoplastic blends (PET/PC, PET/PA and PET/ABS) were studied. Miscibility of components of the blends is limited leading to weak mechanical properties such as low tensile strength and/or elongation at break. Due to that phenomenon compatibilizing additives are also required. As compatibilizing additives olefin-maleic-anhydride copolymer based additives have been used in our experiments. Structure of additives differed from each other both in ratio and length of carbon chains of compounds linked to maleic-anhydride groups. Blends have been studied with PET content ranging from 10 to 90%. As an outstanding result improving of mechanical properties was achieved, for example almost 40% growth was observed in elongation at break of extruded 80/20 PET/PA blends in the presence of 0.2% compatibilizing additive compared to the sample without additive, meanwhile its strength has also improved.Graphic

Observing a Chemical Reaction at a Buried Solid/Solid Interface in Situ.

Chemical reactions are the most important phenomena in chemistry. However, chemical reactions at buried solid/solid interfaces are very difficult to study in situ. In this research, the chemical reaction between two solid polymer materials, a nylon film and a maleic anhydride (MAH) grafted poly(ethylene-octene) (MAHgEO) sample, was directly analyzed at the buried nylon/MAHgEO interface at the molecular level in real time and in situ, using surface and interface sensitive sum-frequency generation (SFG) vibrational spectroscopy. Disappearance of nylon signals indicated a chemical reaction between amine and hydrolyzed amide groups of nylon and MAH groups on the MAHgEO at the buried interface. The appearance of SFG signals from reaction products was also observed at the buried nylon/MAHgEO interface. The mechanism of the observed interfacial reaction was further analyzed. Temperature-dependent SFG experiments were performed to measure the activation energy of the interfacial reaction, enabling a comparison with that reported for the bulk materials. The interfacial chemical reaction between nylon and MAHgEO greatly improved the adhesion of these dissimilar materials. The detailed analysis of a chemical reaction between two polymers at the polymer/polymer buried interface underscores the utility of SFG as a powerful analytical tool to build understanding of buried interfaces and to accelerate the design of interfacial structures with desired properties.

Probing Molecular Behavior of Carbonyl Groups at Buried Nylon/Polyolefin Interfaces in Situ.

Nylon and maleic anhydride (MAH)-grafted polyolefin-based thin co-extruded multilayer films are widely used in packaging applications encountered in daily life. The molecular structure of the nylon/MAH-grafted polyolefin buried interface and molecular bonding between these two chemically dissimilar layers are thought to play an important role in achieving packaging structures with good adhesion. Here, the molecular bonds present at a nylon/maleic anhydride (MAH)-grafted polyethylene buried interface were systematically examined in situ for the first time using sum frequency generation (SFG) vibrational spectroscopy. The carbonyl stretching frequency region of the SFG spectra of a nylon/MAH-grafted polyethylene buried interface showed the presence of hydrolyzed MAH groups grafted to the polyethylene chain and very low levels of unreacted MAH enriched at the buried interface. The ability of SFG to detect these molecular species at the buried interface yields important understanding of the interfacial molecular structure and provides the basis for subsequent in situ studies of the bonding reaction between the grafted MAH and nylon directly at the interface. This understanding may guide the design of multilayer films with improved properties such as enhanced adhesion between polymer layers. The approach used in this study is general and is applicable to study the molecular characteristics of other buried interfaces of significance, such as buried interfaces involving polymers in solar cells, polymer semiconductors, and batteries. Nylon impact modification is another area of interest where the interaction between the MAH-grafted elastomer and the continuous phase of nylon is important.

Cysteamine functionalised reduced graphene oxide modification of maleated poly(propylene)

Graphene oxide (GO) was reduced (rGO) and then functionalised with an amino terminated thiol molecule (cysteamine) via a thiol-ene click chemistry reaction to produce reduced graphene oxide-cysteamine (rGO-cyst). The presence of the C–S bond in the X-ray photoelectron spectrum (XPS) confirmed the reaction between the thiol in cysteamine and both the double bonds present on the rGO surface and the pyrazolic structures formed due to reduction. The rGO-cysyteamine was reacted with polypropylene-graft-maleic anhydride (PP-g-MA) to produce PP-g-MA-rGO-cysteamine, where the free amino group present on the rGO-cysteamine reacts with the maleic anhydride group of PP-g-MA. This was confirmed from solid state 13C Magic-Angle-Spinning, Nuclear Magnetic Resonance (MAS NMR), Fourier transform infrared (FTIR) and XPS studies which demonstrated that a mixture of open and closed ring structures based on amides, imides and imines were formed. Growth of the PP chain on the rGO surface was observed from electron microscopy imaging. Cysteamine acts like a ‘cross-linker’ between the rGO and PP-g-MA, increasing interfacial interaction between the two phases resulting in increased thermal stability and altering the crystallization behaviour of the maleated PP. The approach described could be used to compatabilise graphene oxide and a range of polymers to produce functional composite materials.

Transparent organic/silica nanocomposite coating that is flexible, omniphobic, and harder than a 9H pencil

Coatings that are transparent, wear resistant, flexible, and anti-smudge may be used on foldable touchscreens, for example. However, there have been only few reports on such coatings. This paper reports such a coating. The coating is prepared from the thermal curing of cycloaliphatic epoxy-functionalized oligosiloxanes (CEOS) with PEMA-g-PDMS, poly[ethylene-alternating-(maleic anhydride)] (PEMA) grafted with PDMS side chains. Here CEOS is prepared via sol–gel reactions involving [2-(3,4-epoxycyclohexyl)ethyl]trimethoxysilane, an inexpensive coupling agent. Meanwhile PEMA-g-PDMS is prepared from commercially available PEMA and monoamine-terminated PDMS. The coating is cured via heat-induced ring opening of the epoxide groups of CEOS by maleic anhydride groups of PEMA. With a final PDMS weight fraction of 2.8 wt% and a thickness of 40 µm, the cured coating has a transmittance of 94.9% at 500 nm. On such a coating, test liquids with surface tensions exceeding ~22 mN/m readily and cleanly slide, while ink traces and graffiti paint readily contract. These properties are retained after the coating is abraded with cheesecloth under a pressure of 15.5 kPa for 10,000 cycles. Additionally, this coating exhibits exceptional flexibility. On either side of a PET film, the bilayer film can be bent into a shape with a U cross section without coating damage. While this coating may have practical applications, the chemistry used may be used for the development of other coatings.

Физико-механические свойства композитов на основе полиэтилена различных типов и алюминия

The paper presents the results of a study of the effect of aluminum content on the physic-mechanical properties of composites based on high density polyethylene and low density polyethylene. The properties of metal-filled composites, such as ultimate tensile stress, elongation at break, elastic module, melt flow rate, and heat resistance, were studied. According to the data obtained, the loading of aluminum into the composition of low density polyethylene contributes to a monotonic increase in the ultimate tensile stress and the elastic module. When aluminum is loading into the composition of high density polyethylene, on the contrary, a natural decrease in the ultimate tensile stress and elongation at break of the composites is observed. It is shown that when using a compatibilizer, which is polyethylene modified with maleic anhydride, a significant increase in the ultimate tensile stress of high-density polyethylene composites is observed. A schematic representation of the structure of composites with an interpretation of the probable mechanism of hardening of the material in the presence of a compatibilizer is given. It is shown that the crystallinity of the initial polyethylene has a significant effect on the hardening effect of composites. Electron microscopic micrographs of the structure of a filled composite without and with compatibilizer are given. A comparative assessment shows that in the presence of a compatibilizer, aluminum particles are in the bulk of the polymer matrix, i.e. are not in an isolated state. It is assumed that HDPE macrochains free of maleic anhydride (MA) are involved in the formation of crystalline formations, and small sections of macrosegments containing polar groups of MA are concentrated mainly in amorphous regions and in defects in crystalline structures in the form of passage chains. The concentration of PEMA macrosegments containing MA in the narrow amorphous space of HDPE favorably affects the increase in the adhesive forces of interaction on the surface of aluminum particles, which affects the preservation of the ultimate tensile stress at a relatively high level over a wide range of aluminum concentrations.

Properties of Blends from Polypropylene and Recycled Polyethylene Terephthalate using a Compatibilizer

Polyethylene Terephthalate (PET) is a major constituent of the plastic waste generated on a day-to-day basis. Replacing a proportion of the virgin Polypropylene (PP) with recycled Polyethylene Terephthalate (r-PET) through polymer blending is cost-effective and sustainable method to increase the mechanical characteristics of PP. A compatibilizer namely Polypropylene grafted maleic anhydride (PP-g-MAH) is utilized to reduce immiscibility between them through chemical reactions involving the maleic anhydride group. In this study, PP/r-PET blend ratio is maintained at 80/20. The polymer blends prepared by twin screw extrusion are converted to test specimens by injection moulding. The mechanical and thermal properties of the blends are studied by performing characterization techniques like Tensile Tests and Differential Scanning Calorimetry (DSC). Fourier Transform Infrared Spectroscopy (FTIR) analysis shows the reaction occurring at the interface during compatibilization. Scanning Electron Microscopy (SEM) suggests the significance of compatibilizer in the microstructure development of the blend for the effective dispersion of the r-PET in PP. The crystallization temperature of PP is moved to higher temperatures in the presence of both the r-PET and the compatibilizer as evident from the DSC analysis. The addition of the compatibilizer improved the tensile strength, elongation at break and the modulus of elasticity of the blend. The blend containing 4% PP-g-MAH exhibited the optimum set of properties.

Preparation of high-strength SEBS nanocomposites reinforced with halloysite nanotube: Effect of SEBS-g-MA compatibilizer

Poly(styrene -b-ethylene- co-butylene -b-styrene) (SEBS)/organophilic halloysite nanotube (Org-HNT) nanocomposites were prepared by solution mixing and then compression molded. Maleic anhydride grafted SEBS (SEBS- g-MA) was also used as a compatibilizer in preparation of SEBS/SEBS- g-MA/Org-HNT ternary nanocomposites. Surface morphologies and both static and dynamic mechanical analyses as well as thermal stabilities of the nanocomposites were carried out. Both the binary and ternary nanocomposites exhibited higher tensile moduli, tensile strength, and toughness values compared to neat SEBS. The elastic modulus was found to increase about 385% and 320% with addition of 3 and 5 phr Org-HNT into the SEBS matrix, respectively, while the maximum toughness was achieved via SEBS-5H composite with an increase of 45%. The ternary nanocomposite having 3 phr Org-HNT and 10 phr SEBS- g-MA (3H10SMA) gave about a 325% and 103% increase in the elastic modulus and toughness, respectively, together with a 75% increase in the tensile strength as the maximum value. This result was ascribed to interactions of the surface of the nanotubes with the maleic anhydride (MA) group of the compatibilizer. The same nanocomposite was also found to have two times higher dynamic storage modulus at 25°C than neat SEBS and almost the same damping value, which is an indication of improvement in the elastic character of SEBS without impairing its damping ability. Although a much higher damping value was obtained via use of 20 phr SEBS- g-MA with the same amount of nanotubes, the corresponding storage modulus decreased too much, close to that of neat SEBS. The enhanced tensile modulus, strength, and toughness of the 3H10SMA nanocomposite, which is consistent with its dynamic mechanical properties, indicate a good balance between the toughness/damping and stiffness. Moreover, all the nanocomposites exhibited better thermal stabilities than neat SEBS, showing higher midpoint degradation temperatures and peak maximum temperatures at which the maximum degradation occurs.