Maleated Poly Research Articles

4D printable maleated poly(styrene-b-ethylene/butylene-b-styrene) / Poly(ethylene-co-vinyl acetate) thermoplastic elastomer blends; effects of blend composition on shape memory and mechanical properties

Shape memory polymers are attracting attention in materials science with their responsive properties and their application areas are gradually developing. By adapting these materials to the additive manufacturing process, four-dimensional (4D) printing technology has been developed. In this study, novel thermo-responsive shape memory polymer blends were prepared for high temperature applications from commercially available polymers using maleated poly(styrene-b-ethylene/butylene-b-styrene) (SEBS-g-MA) and poly(ethylene-co-vinyl acetate) (EVA) and their applicability in three-dimensional (3D) printing was explored. The presence of SEBS-g-MA led to an increase in the degree of crystallization and glass transition temperature of EVA, accompanied by a decrease in crystallization temperature. As the EVA content increased, the blend morphology transitioned from droplet to co-continuous structure. Higher EVA content resulted in an increase in Young's modulus, but a decrease in tensile strength. Nevertheless, these blends exhibited exceptional elongation at break, surpassing 1200%. The blend comprising 70 wt% SEBS-g-MA and 30 wt% EVA demonstrated a synergistic effect, yielding the highest values for elastic modulus, creep resistance, and storage modulus. Furthermore, the blend with 60 wt% SEBS-g-MA and 40 wt% EVA exhibited optimal shape memory performance, achieving a shape fixing ratio of 93.1% and a shape recovery ratio of 98.7%. The conducted analyses demonstrated that the shape recovery of the produced blends could be adjusted according to temperature, and the blends were able to consistently replicate the shape memory effect across multiple cycles. A filament was manufactured for a 3D printer from the blend of 60 wt% SEBS-g-MA and 40 wt% EVA. Using this filament, 4D models having complex geometries were successfully printed. The produced models were able to maintain their temporary shapes to a significant degree. When triggered by heat, these models rapidly returned to their original shapes within a very short period.

Preparation and characterization of super-toughened PA6/r-PVB blends with “transplanted” multicore morphology by reactive compatibilization

Super-toughened polyamide 6 (PA6) material was fabricated by applying a feasible and effective method involving reactive melt blending of PA6 and residue of plasticized poly(vinyl butyral) (r-PVB)/maleated poly(ethylene-1-octene) (POE-g-MA) masterbatch, in which the multicore structure could be formed in-situ in PA6 matrix. Interfacial, rheological and morphology measurements confirmed that the POE-g-MA was encapsulated by r-PVB in PA6 matrix. The sharp brittle-ductile transition was observed at a critical interparticle distance (τc) about 0.30 μm for PA6/r-PVB/POE-g-MA blends, and the impact strength was 22–24 times higher than that of neat PA6. The flexibility of r-PVB/POE-g-MA and the strong interfacial adhesion among the three blending composition were responsible for the super toughness of PA6/r-PVB/POE-g-MA ternary blends. The DSC results suggested that the improvement of toughness was also related to the decrease in glass transition temperature (Tg) and degree of crystallinity (Xc) of PA6 matrix.

A packaging material from a waste paper/sugar cane stalk composite: Preparation and properties

Abstract A highly efficient method was developed to produce a new biocomposite (PF) from waste paper and sugar cane stalk (SF) using four types of adhesive: maleated poly(vinyl alcohol) (PVAM), natural rubber-graft-cassava starch (NC), modified cassava starch (SA) and a blend between the NC and SA (NS). The effects of adhesive type and concentration, and the SF contents on the properties of the composite were investigated. The impact strength of the PF formed with the PVAM, NC, SA and NS increased as adhesive concentration increased due to higher chemical interactions and varying the amount of adhesive, affected the hardness of the PF. Moreover, the swelling ratio in water of the PF decreased with increasing adhesive contents due to a higher chemical reaction between them. Increasing the SF content of the PF formed with all the adhesives, reduced their impact strength occurred due to poor adhesive between the SF and the adhesives. The swelling ratio of the PF was significantly improved by the addition of the SF due to its porosity. The density of the PF formed with the PVAM, NC and NS decreased as a function of the SF owing its porosity. The optimum adhesive for the PF composite was NS based on the mechanical strength, swelling ratio and morphology of the PF thus formed.

Preparation and Characterization of Poly(L-lactide-co-glycolide-co-ε-caprolactone)/1,4-Butanediamine Modified Maleated Poly(D,L-lactide-co-glycolide) Blend Porous Films

Poly(L-lactide-co-glycolide-co-ε-caprolactone) (PLLGC) and 1,4-butanediamine modified maleated poly(D,L-lactide-co-glycolide) (BMPLGA) were both synthesized by ring-opening polymerization with stannous octoate as catalyst. Then PLLGC/BMPLGA blend porous films were prepared by using NaCl particles as a porogen through a solvent casting/particle leaching method. The PLLGC/BMPLGA blend porous films were characterized by Fourier transform infrared spectroscopy, gel permeation chromatography and scanning electron microscopy. The tensile properties of the PLLGC/BMPLGA porous films were also studied. The results showed that the content and size of the NaCl porogens had significant effects on the porosity of the PLLGC/BMPLGA porous films. The tensile strength and elongation percentage of the porous films decreased with increasing porogen content. Thus, both the pore structure and mechanical properties of the porous PLLGC/BMPLGA blend films can be controlled by changing the amount and size of the porogen.

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.

Unveiling the Effects of In Situ Layer–Layer Interfacial Reaction in Multilayer Polymer Films via Multilayered Assembly: From Microlayers to Nanolayers

AbstractMultilayered polymer films are increasingly used in the daily life, but their macroscopic properties are always limited by the layer–layer interfacial compatibility. In this work, the influence of interface modification through in situ layer–layer interfacial reaction during a multilayered assembly is revealed from micro‐ to nanolayer films, based on maleated poly(vinylidene fluoride) and polyamide‐6. In the presence of interfacial reaction and confinement, layer architecture and microstructure are highly dependent on the number of layers. Specifically, for nanolayer films having smaller layer thicknesses and higher reaction extent, layer integrity is reduced with the occurrence of interfacial instabilities. Depending on the microstructural evolution from multilayer assembly, those films exhibit quantitatively different extensional rheological and dielectric properties from micro‐ to nanolayers. More importantly, dielectric spectroscopy reveals the contribution of copolymer‐rich interphases to the dielectric performance of micro/nanolayered films. Additionally, charge transport dynamics in nanolayered films also differ significantly from their microlayered counterparts. They are attributed to the strong dependence of interfacial reaction extent and resulting microstructure on the number of layers and layer thicknesses. This work clearly illustrates how the control of layer–layer interfacial reaction in micro/nanolayer assembly can tune the interfacial, microstructure, and macroscopic properties of multilayered products.

Highly toughened PA6 using residue of plasticized PVB film via two-step reactive melt blending

For sustainable development and environmental protection, residue of plasticized poly(vinyl butyral) film (r-PVB) was reactive mixed with maleated poly(ethylene-1-octene) (POE-g-MA) to obtain masterbatch in a torque rheometer, which was then melt extruded with polyamide 6 (PA6). The existence of POE-g-MA could efficiently modulate the phase morphology and performance of incompatible PA6/r-PVB blends due to its reactivity with PA6 and r-PVB. Moreover, increasing the POE-g-MA content could significantly enhance the interfacial adhesion among the components and was a favor to the formation of “multicore” structure (POE-g-MA encapsulated by r-PVB) in the ternary blends, which were two key issues to obtain high impact toughness. In particular, the maximum impact strength of the obtained super-toughened PA6 blends was about 137.5 kJ/m2, 24 times higher than that of neat PA6. The appearance of massive shear yielding strips in matrix and large deformation of the dispersed phase were the main source of energy dissipation under the impact loading. This work provides a feasible, low-cost but very effective strategy to fabricate super-toughened PA materials.

Environmentally Friendly Novel Maleated Poly(vinyl alcohol) Grafted 1, 4-Butanediol Modified with Biopolymer for Encapsulation of Capsaicin

Nowadays, hydrogels are widely used in many fields, for instance as biosensors, in tissue engineering and in agriculture due to their high swelling behavior in water and their softness. The objective of this work was to study the preparation and physical properties of maleated poly (vinyl alcohol) (PVAM)-graft-butanediol (BDO) (PVAM-graft-BDO) using K2S2O8 as an initiator. The highest grafting efficiency of 92% was found at 7:3 PVAM-graft-BDO. The swelling behavior of the PVAM-graft-BDO increased with an increasing BDO content. The highest swelling ratio of the PVAM-graft-BDO of 250% was found at 7:3 PVAM:BDO. Moreover, the maximum tensile strength of the PVAM-graft-BDO was observed at 9:1 PVAM:BDO. The elongation at break of the PVAM-graft-BDO was improved by the addition of natural rubber-graft-cassava starch (NS). The PVAM-graft-BDO was used as a polymer matrix for the encapsulation of capsaicin. The results showed that the rate of capsaicin release from the polymer matrix in a water medium was controlled by the BDO portion and the NS content. After use, it was easily degraded in natural soil.

In-vitro degradation behavior and biological properties of a novel maleated poly (D, L-lactide-co-glycolide) for biomedical applications

Synthesized biodegradable polymers with controlled degradability and good biological safety would be useful in biomedical applications. In this work a novel maleated poly(D,L-lactide-co-glycolide) (MPLGA) was melt copolymerized from maleic anhydride, D,L-lactide and glycolide monomers. The degradation behavior in phosphate-buffered solution (PBS) was investigated and the biological properties were studied by using fibroblastic cells cultured in an extract of MPLGA and by an in-vitro cell cytotoxicity test. The results indicated that the MPLGA was successfully obtained using the melt-copolymerization method. The maleic anhydride groups in the MPLGA led to a faster degradation in PBS than PLGA. Fibroblastic cells showed normal morphologies in MPLGA extracts, and the MPLGA materials showed no cell cytotoxicity. The in-vitro biological properties indicated that the obtained MPLGA had good biocompatibility and would be useful for medical applications.

Development of a novel pH-sensitive polymer matrix for drug encapsulation from maleated poly(vinyl alcohol) grafted with polyacrylamide

Hydrogels are widely used in medical, food and other applications due to their good water absorption without dissolution. The objective of this work was to synthesize a maleated poly(vinyl alcohol) (PVAM) grafted copolymer with anionic polyacrylamide (PAM) (PVAM-graft-PAM) using K2S2O8 as an initiator in an eco-friendly process. The chemical structure of the PVAM-graft-PAM was confirmed by FTIR. The influences of the PVAM/PAM ratio and the natural rubber-graft-cassava starch (NS) and PVAM/PAM ratio on the properties of the PVAM-graft-PAM were investigated. It was observed that the swelling ratio of the sample was enhanced with increasing PAM portions in the PVAM-graft-PAM. However, as the quantity of NS in the graft copolymer increased, the swelling ratio decreased. In addition, the PVAM-graft-PAM was sensitive to variation in pH due to the presence of carboxylic and amide groups on the grafting structure. After the preparation of the PVAM-graft-PAM, it was used in the controlled release of retinoic acid. After use, the resulting hydrogel degraded easily in natural soil.

PBAT/thermoplastic starch blends: Effect of compatibilizers on the rheological, mechanical and morphological properties

The effect of maleic anhydride (MA), citric acid (CA) and maleated poly(butylene adipate-Co-terephthalate) PBAT (PBATg-MA), as compatibilizer, on properties of blends of plasticized starch/PBAT in a weight ratio of 60/40 were investigated using rheological measurements, tensile tests, SEM observations and mechanical dynamic analyses. A strong evolution in the mechanical, morphological and rheological properties of the blend was observed according to the type of additives used. The type of compatibilizer was shown to control the morphology and continuity development of the TPS/PBAT 60/40 wt% blend. In the absence of the compatibilizer and in presence of PBATg-MA, the PBAT was the continuous phase, while the TPS became the continuous one in presence of MA and CA. These evolutions were explained by the change in the melt rheological properties of TPS in the presence of the compatibilizer and its aptitude to promote interfacial adhesion between TPS and PBAT phases. A huge evolution in the tensile strength and strain at break were also observed according to the structure of the compatibilizer.

An insight into the interaction between functionalized thermoplastic elastomer and layered double hydroxides through rheological investigations

Abstract Nanocomposites based on maleated poly(styrene-(ethylene-co-butylene)-styrene) copolymer (SEBSgMA) and organo-modified layered double hydroxide (OLDH) have been formulated with the aim to investigate the effects of interfacial interactions between the grafted maleic anhydride groups of the copolymer and the OLDH nanolayers on the rheological properties of nanocomposites. The spectroscopic analysis indicates the establishment of specific polymer/nanofiller interactions, whose extent has been highlighted through morphological and rheological investigations. Specifically, oscillatory melt rheology and shear relaxation tests have been considered in order to deeply investigate the interfacial bridging interactions. Obtained results highlight that SEBSgMA-based nanocomposites containing a high amount of OLDH show solid-like rheological behavior, quite similar to that of crosslinked polymers, attributable to the formation of a gel-like structure.

Investigating the properties of maleated poly(lactic acid) and its effect on poly(lactic acid)/cellulose nanofiber composites

Abstract In this research, maleated poly(lactic acid) (PLA-g-MA) was manufactured by different levels of maleic anhydride (MAH). Also PLA-g-MA effects as a compatibilizer were investigated on PLA/cellulose nanofiber (CNF) composites. The grafting reaction was performed in the presence of dicumyl peroxide (DCP) as an initiator at constant level (0.2 phr) via reactive extrusion. Furthermore, the effects of four different levels of MAH (1–4 phr) were studied on the physical properties of PLA grafted films. We used the Fourier transform infrared (FTIR) and titration methods for confirmation of the grafting process. Based on the titration method, the greatest amount of yield was gained by 4 phr of MAH in grafting. Contact angle analysis shows that increasing the amount of MAH led to a decrease in the contact angle of films. Moreover, the glass transition temperature (Tg) and % crystallinity were decreased by increasing MAH content. PLA-g-MA was added to the composites in two levels of 3% and 5% in total. CNF was used at a constant level of 5%. The thermal, morphological and mechanical properties of nanocomposites were determined as a function of PLA-g-MA content using thermogravimetric analysis, heat distortion temperature (HDT) and tensile testing. All the prepared nanocomposite materials showed improvement in the mechanical and thermal properties compared to neat PLA.

Preparation and Properties of Novel Maleated Poly (D, L-lactide-co-glycolide) Porous Scaffolds for Tissue Engineering

ABSTRACTThree-dimensional biodegradable porous scaffolds play an important role in tissue engineering. A new polymer based on maleated poly(lactic-co-glycolic acid) (MPLGA) was synthesized using direct melt copolymerization from maleic anhydride (MAH), D, L-lactide, and glycolide monomers. MPLGA porous biodegradable scaffolds were prepared by a solution-casting/salt-leaching method. The effects of content and size of the NaHCO3 porogen on the compressive strength of the MPLGA scaffolds were investigated, and the effect of content of the porogen on the porosity of the MPLGA scaffolds was also studied. The results indicated that MAH was grafted onto PLGA successfully and MPLGA scaffolds with interconnective and open pore structure were obtained. Increasing content of NaHCO3 porogen resulted in an increase of porosity and decrease of the compressive strength of the MPLGA scaffolds with the compressive strength of the scaffolds also decreasing with increasing porogen size.

Preparation and properties of poly(lactic acid)/cellulose nanocrystals nanocomposites compatibilized with maleated poly(lactic acid)

High thermally stable cellulose nanocrystals (CNCs), prepared by acid hydrolysis, were obtained by combination of alkali treatment (label as CNCs) and mixing with poly(ethylene oxide) (PEO). Dry mixture of PEO/CNCs (oCNCs) was subsequently introduced into poly(lactic acid) (PLA) matrix by melt extrusion and then compatibilizing with maleated PLA. The effects of compatibilization with maleated PLA (PLA‐g‐MAH) on the structure and properties of PLA/PEO/CNCs nanocomposites were investigated. PLA/PEO/CNCs/PLA‐g‐MAH nanocomposites displayed improved interfacial adhesion as compared to PLA/PEO/CNCs composites. Differential scanning calorimetry analysis showed enhanced crystallization ability for the resulting nanocomposites. The significant enhancement of thermal stability and tensile parameters, as strength and elongation at break were observed for the composites, which was primarily attributed to strong interfacial adhesion between filler and matrix and the uniform dispersion of CNCs. POLYM. COMPOS., 39:3092–3101, 2018. © 2017 Society of Plastics Engineers

Dynamic viscosity of maleate poly(vinyl alcohol) and its copolymer measured by rheometer

The objective of this work was to study the mechanism of gel formation for maleated poly(vinyl alcohol) (PVAM) and maleated poly(vinyl alcohol)-graft-gelatin (PVAM-g-GT) in solution form using a rheometer to monitor changes in the dynamic viscosity and shear stress-shear rate curves. The dynamic viscosity of the PVAM solution increased and then decreased with increases in the shear rate, and the dynamic viscosity of the PVAM solution decreased as a function of the MA content increased. The dynamic viscosity of the PVA solution was higher than that of the PVAM solution due to its gel formation. Moreover, the dynamic viscosity of the PVAM solution increased and then decreased over long periods. Over a storage time of 2 days, the dynamic viscosity of the PVAM decreased due to chain scission. The PVAM solution showed shear thickening in the first stage and shear thinning in the last stage of the experiment. The dynamic viscosity of the PVAM-g-GT solution continued to decrease continually at a constant rate with increases in the shear rate because the H-bonding was broken at higher shear rates. This was probably because the energy of the H-bonding interaction is less than the energy of carbon–carbon covalent bonding resulting in broken H-bonding both intra-chain and inter-chain H-bond.

Evaluation of the genotoxic potential of modified clays destined to food packaging through the micronucleus assay

Maleated poly(propylene carbonate) (PPC-MA)/organo-montmorillonite (OMMT) nanocomposites were first prepared via melt end-capping poly(propylene carbonate) (PPC) with maleic anhydride (MA) and melt-mixing the PPC-MA with commercial OMMT without and with hydroxyl groups in surfactants: Cloisite 20A (C20A) and Cloisite 30B (C30B), respectively. Intercalated and partially delaminated morphologies were corroborated via X-ray diffraction (XRD) and transmission electron microscopy (TEM). Dynamic mechanical analysis (DMA) revealed that PPC-MA was evidently reinforced by the partially delaminated C30B platelets. From XRD patterns of statically annealed PPC-MA/C20A and PPC-MA/C30B mixtures and Fourier transform infrared (FTIR) results of equivalent nanocomposites, partial delamination of C30B in PPC-MA was confirmed to be relevant to diffusion of PPC-MA molecular chains in C30B galleries, grafting of PPC-MA to C30B platelet surfaces and further separation of C30B platelets.

Green robust pH–temperature-sensitive maleated poly(vinyl alcohol)-g-gelatin for encapsulated capsaicin

To date, smart hydrogels are widely used in the biomedical field such as wound dressings, artificial tendons, drugs and tissues owing to its sensitivity on environmental medium. The present work was focused on the preparation of a maleated poly(vinyl alcohol) (PVAM)-g-gelatin (GT) (PVAM-g-GT) from the PVAM and the GT in aqueous solutions using K2S2O8 as an initiator. The characteristic bands of the novel smart PVAM-g-GT hydrogel were observed with peaks at 3288, 1541 and 1238 cm−1 observed by FTIR. The increasing amounts of GT resulted in a decrease of the crystallinity. The swelling ratio in the water increased and the contact angle decreased with an increase of GT in the graft copolymer due to an increase of the hydrophilic groups in the hydrogel. In addition, the tensile strength of the novel smart PVAM-g-GT increased with an increase of the GT. The highest tensile strength and elongation at break were found at 8:2 PVAM:GT. Moreover, PVAM-g-GT shows a good responsibility to pH and temperature and it was used to a polymer matrix for encapsulation of capsaicin. A lower capsaicin release rate from the PVAM-g-GT hydrogel was obtained when immersed at pH 8 than at pH 2 due to hydrogen bond between the capsaicin and the polymer matrix.

A rheological method for the determination of “super toughness point” of polymer blends: A blend system of nylon1212 with maleated poly(ethylene-octene)

The rheological behavior of a reactive blend system of nylon1212 with maleic anhydride grafted poly(ethylene-octene) was studied in correlating with the key mechanical parameters. Results illustrated that the “gel points” acquired from the dynamic rheological data and the “super-toughness points” of the blends have a corresponding relationship. Thus, just by simple composition designs and a small amount of samples, the super-toughness point could be conveniently determined by the dynamic rheological measurements. Furthermore, special “double network” morphology at the gel point was directly observed for the first time and the new mechanism of super-toughness has also been discussed.

Preparation and properties of a novel environmentally friendly film from maleated poly(vinyl alcohol) grafted with chitosan in solution form: the effect of different production factors

A maleated poly(vinyl alcohol) (PVAM)-g-chitosan (CS) (PVAM-g-CS) film was prepared in solution form using potassium persulfate (K2S2O8) as an initiator. The influence of the PVAM:CS ratio, the reaction time and temperature and the concentration of K2S2O8 on the properties of the PVAM-g-CS were investigated. Ether linkage of the PVAM-g-CS was observed at 1154 and 1089 cm−1 by ATR-FTIR. The conditions for grafting CS to PVAM were developed and optimized. The highest degree of grafting was observed at a ratio of 9:1 PVAM:CS. The optimum grafting conditions were found to be 50 °C for a reaction time of 1 h, with a ratio of PVAM:CS of 9:1 and a concentration of 0.5 % K2S2O8. The maximum and minimum swelling ratios were 150 and 330 %, respectively. The tensile strength of the PVAM was enhanced after the incorporation of CS in the PVAM. The highest tensile strength of 24 MPa was found at a ratio of 5:5 PVAM:CS. The PVAM-g-CS shows a high efficiency of controlling capsaicin release in base–acid medium and was easily biodegradable in natural soil especially with high proportions of CS.