Compatibilizer Content Research Articles

On The Crystallinity Of Eco Bioplastics Packaging Using DSC Techniques

The aim of this study is to examine Eco Bioplastics Packaging containing LDPE/CS. Effects content concentration of corn stalk and inclusion compatibilizer on the crystallinity and morphology of Eco Bioplastics Packaging biocomposites. It was found that the by using similar filler loading, compatibilized Eco Bioplastics Packaging has revealed higher enthalpy and crystallinity of Eco Bioplastics Packaging with MAPE. Additionally, the addition of MAPE improved the interfacial interaction between corn stalk and LDPE biocomposites, as confirmed by SEM analysis. Keywords: Corn Stalk Powder (CSP), Maleic Anhydride Polyethylene (MAPE), Light Density Polyethylene (LDPE)

Multifractal detrended fluctuation analysis on the fracture surface of polycarbonate and acrylonitrile-butadiene-styrene alloy

Multifractal detrended fluctuation analysis (MF-DFA) has been carried out to evaluate the multifractal properties of the fracture morphology for Polycarbonate (PC) and Acrylonitrile-butadiene-styrene (ABS) alloy, and the relationship between the long-range correlation parameter of the samples fracture - Hurst exponent and fractal dimension was explored and analyzed. The results suggest that the existence of multifractal properties within the micrometer scale domain we investigated for the fracture surface of PC/ABS alloy samples. The Hurst exponent and fractal dimension can both be used to measure and characterize the fracture surface morphology of the PC/ABS alloys. As the content of compatibilizer PP-g-MAH increased, the tensile strength of PC/ABS alloy decreased, the fracture surface peaks tend to dominate, the Hurst exponent increased, the fractal dimension decreased, and its strength retention rate increases, displaying persistence.

Supertoughened Polylactic Acid/Polybutylene Adipate Terephthalate Blends Compatibilized with Ethylene-Methyl Acrylate-Glycidyl Methacrylate: Morphology and Mechanical Properties by the Response Surface Methodology.

Optimized extrusion melt-blending of polylactic acid (PLA) polymer with a minor biopolymeric phase, polybutylene adipate terephthalate (PBAT), and compatibilized with random ethylene-methyl acrylate-glycidyl methacrylate terpolymer (EMA-GMA, Trademark: Lotader AX-8900) led to an outstanding improvement in mechanical properties. At the noncompatibilized PLA-PBAT (80-20) blend point, significant enhancement (∼4500%) in toughness and elongation-at-break was already obtained without compromising any elastic properties. The effect of the compatibilizer content on the mechanical properties of the PLA-PBAT (80-20) blend was investigated by an optimal custom response surface methodology. Thus, 2 wt % Lotader content was determined to be optimal by a numerical optimization methodology with a desirability value, D, of 0.882 to maximize toughness and elongation-at-break. The compatibilization and thermal behavior of the Lotader-modified blends were analyzed by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Upon adding the compatibilizer, the original phase-separated morphology of the blends changed from PBAT quasi-spherical domains to nearly elongated elliptical ones. It was also found that the interfacial boundary line of the domains faded away, which revealed that interfacial compatibility was achieved. The thermostability of the blends remained largely unaltered following the incorporation of PBAT and Lotader. Moreover, while PBAT exhibited a minor influence on the crystallinity of PLA, Lotader had no discernible impact on crystallinity, as evidenced by the DSC thermograms. Thus, the compatibilizer at the optimal point in the optimized blend ratio led to the formation of a phase-separated morphology that combined internal cavitation, interfacial cavitation, and strong adhesion features at the right proportions in the microstructure which underlies the micromechanisms driving the remarkable enhancement of as much as 7100% in toughness and ductility.

Effects of compound compatibilizer and CaTiO3 filler on the properties of polypropylene/polyphenylene ether/glass fiber composites

AbstractThe present study used polyphenylene ether/Polypropylene/glass fiber (PPO/PP/GF) composites as the matrix material to obtain the dielectric plate material to be used in the dielectric phase shifters for 5G base stations. First, the reinforcement effect of the compound compatibilizers comprising PP‐g‐MAH and SEBS‐g‐MAH on the PPO/PP/GF composites was investigated. The experimental results revealed that the compound compatibilizers could dramatically improve the compatibility and performance of the PP/PPO/GF composites through synergistic compatibility. Next, the crystallization effect of CaTiO3 fillers on the PPO/PP/GF composites was investigated. The DSC analysis revealed that using a small amount of CaTiO3 promoted the crystallization of PP, while using a large amount of CaTiO3 inhibited the crystallization effect. At a compatibilizer content of 6 wt% and CaTiO3 in the range of 10–85 wt%, the CaTiO3/PP/PPO/GF composite presented a continuously adjustable dielectric constant (εr = 2.32–20.9), low dielectric loss (tanδ < 0.0019), and high heat resistance (VST = 169.5–177°C), and could, therefore, be used as a dielectric plate material in the dielectric phase shifters for 5G base stations.Highlights The compound compatibilizers comprising PP‐g‐MAH and SEBS‐g‐MAH could dramatically improve the compatibility and performance of the PP/PPO/GF composites through synergistic compatibility. A small amount of CaTiO3 promoted the crystallization of PP and a large amount of CaTiO3 inhibited the crystallization effect. The CaTiO3/PP/PPO/GF composites could serve as ideal dielectric plate materials in the development of dielectric phase shifters for 5G base stations.

Effect of wood flour and compatibilizer content on the properties of wood-plastic composites

Wood-plastic composites (WPC) with are prepared by melting and mixing wood flour (WF) and thermoplastics which has green and biodegradable advantages and is of great significance in the development of the era of global resource scarcity. In this work, recycled polypropylene and WF were used as raw materials and commercially available maleic anhydride grafted polypropylene (MAH-g-PP) was used as a compatibilizer. The extrusion injection molding method was used and investigated by varying the amount of WF and compatibilizer added. The composites were analyzed for micro-morphology, melt mass flow rate, mechanical properties, and thermal stability by scanning electron microscopy (SEM), melt flow rate tester (MFR), electronic universal testing machine, and thermogravimetric analysis (TGA). According to the results, WF shows a positive effect in terms of storage and loss modulus of the composites, but it shows a negative effect in terms of thermal stability and mechanical properties. As an effective compatibilizer, MAH-g-PP plays an important role in improving the mechanical properties of the composites, especially at an additional level of 4 wt%, which maximized the overall performance of the composites.

Polyurethane modified asphalt mixture incorporating waste glass with a wide particle size range: Preparation and performance evaluation

Increasing the utilisation rate of waste glass in asphalt mixtures, especially that with a wide range of particle sizes, is of great importance to resource recycling, while it may bring drawbacks to the engineering performance of asphalt mixtures. Incorporating polyurethane (PU) as a modifier can enhance asphalt mixture's performance, but there is limited research considering the usage of waste glass as aggregates. In this study, PU modified asphalt mixtures were prepared, incorporating waste glass particles ranging in size from 2.36 mm to 9.5 mm as a portion of the aggregates. Optimal preparation methods and mix designs for the PU-modified asphalt binder were determined through a series of tests designed based on Orthogonal method. The performances of the PU-modified asphalt binders were then evaluated to guide the selection of the optimal preparation method and mix design. PU-modified waste glass asphalt mixtures were then prepared and their engineering performances were assessed at various glass-to-aggregate ratios. The results show that scheme PU-1 with a shearing temperature of 140°C, a shearing time of 10 min, a PU content of 10% and a compatibiliser content of 2% is suggested for preparing the PU-modified asphalt binder, which shows the best performances due to superior chemical modification and compatibility. Higher glass content decreases the high/low-temperature performance, but it can be improved by adding silane coupling agent or hydrated lime, with the latter showing better results. The incorporation of glass particles has little impact on anti-sliding performance, and asphalt mixtures maintain excellent anti-sliding properties up to a 20% replacement rate. Overall, the performance of the asphalt with waste glass up to 15% can meet the specification requirements. This novel approach offers a potential solution to enhance the incorporation of waste materials in asphalt construction, contributing to sustainable and environmentally-friendly road construction.

Rheological and Thermal Characterization of Glycerol Monostearate (GMS) as Compatibilizer on Polyethylene-Palm Stearin Composite

Addition of high percentage of palm stearin (PS) into a blend with high density polyethylene (HDPE) may result in the blend instability and poor flowability of the composite during injection moulding process. The undesirable effect of the PS addition arises from lack of interaction between the PS and HDPE matrix. To improve the interaction between the two components, a compatibilizer was added to the blend. The objective of this work is to study the effect of glycerol monostearate (GMS) compatibilizer concentration (1-5 wt%) on the HDPE-PS composite with PS content of 40 wt.%. The thermal properties of the HDPE-PS composite were characterized using torque analysis, differential scanning calorimetry (DSC) analysis and rheology analysis. It was found that melting temperature of the HDPE-PS composite decreases with GMS concentration. The presence of GMS in the HDPE-PS composite had improved composite flowability indicate suitability of the GMS as compatibilizer for the HDPE-PS composite.

Effect of compatibilizer and polyhedral oligomeric silsesquioxane on mechanical, thermal, and morphological properties of polyamide6/poly (ethylene-co-vinyl acetate) composites

The mechanical properties and morphology of polyamide 6/maleic anhydride grafted ethylene-co-vinyl acetate (PA6/EVA-g-MA) ternary composites are considered a function of compatibilizer (EVA-g-MA) amount at a mixing combination of 20 wt% dispersed phase (combination of EVA and the compatibilizer). 1–7 wt% compatibilizer are added to PA6/EVA-g-MA, whereas the PA6 doping is kept constant at 80 wt% in the ternary composites. Furthermore, 0.5, 1, 3, and 5 wt% octa-Isobutyl POSS (OIP) is used for reinforcement. The thermal, mechanical, and morphological properties of PA6/EVA-g-MA composites have been studied through DSC, TGA, DMTA, traditional mechanical measurements, and SEM. Tensile strength and Young’s modulus declined by increasing the compatibilizer concentration. The impact strength of PA6/compatibilizer improved considerably up to 3 wt% of the compatibilizer and then decreased. TGA analysis demonstrated a considerable improvement in the thermal stabilities of the nanocomposites by raising the OIP amount. The results of DMTA, including Tg, and DSC analysis demonstrated that the inclusion of OIP in PA6/compatibilizer considerably changed the thermal properties of only PA6 in PA6/compatibilizer. Incorporating OIP into the composite up to 1 wt% improved its modulus, tensile, and impact strength.

Defining the Effect of a Polymeric Compatibilizer on the Properties of Random Polypropylene/Glass Fibre Composites

Random polypropylene composites reinforced with short glass fibres have been successfully fabricated by melt-mixing. Polypropylene grafted with maleic anhydride (PP-g-MA) was added to the composites, which was expected to act as a compatibilizer and greatly limit the negative effects known to arise from the feeble polymer matrix/glass fibre interfaces. The effect of compatibilizer concentration on the structural, mechanical and thermal behaviour of the composites has been investigated. The results revealed an improvement of the glass fibre/matrix interaction upon the addition of the compatibilizer, which resulted in enhancing the overall material stiffness and the ability of the matrix to store energy. In particular, the lowering of the glass transition and the investigation of the fracture surfaces of the composites confirmed the improved PPR/fibre adhesion. Examination of the tensile elongation indicated the improvement of the Young’s modulus and yield strength with the addition of PP-g-MA, while the storage modulus was also shown to be significantly increased. These results confirmed the versatility and efficiency of the approach presented in this work to improve the thermomechanical properties and sustainability of PPR and promote its usage in industrial applications and commercial manufacturing.

Properties Optimization of Polypropylene/Montmorillonite Nanocomposite Drawn Fibers.

In this study, the mechanical properties and thermal stability of composite polypropylene (PP) drawn fibers with two different organically modified montmorillonites were experimentally investigated and optimized using a response surface methodology. Specifically, the Box-Behnken Design of Experiments method was used in order to investigate the effect of the filler content, the compatibilizer content, and the drawing temperature on the tensile strength and the onset decomposition temperature of the PP composite drawn fibers. The materials were characterized by tensile tests, thermogravimetry, and X-ray diffraction. Two types of composites were investigated with the only difference being the type of filler, namely, Cloisite® 10A or Cloisite® 15A. In both cases, statistically significant models were obtained regarding the effect of design variables on tensile strength, while poor significance was observed for the onset decomposition temperature. Nanocomposite fibers with tensile strength up to 540 MPa were obtained. Among the design variables, the drawing temperature exhibited the most notable effect on tensile strength, while the effect of both clays was not significant.

Poly(butylene terephthalate)/poly(ethylene glycol) blends with compatibilizers

AbstractPolymer blend systems offer a versatile approach for tailoring the properties of polymer materials for specific applications. In this study, we investigated the compatibility of polybutylene terephthalate (PBT) and poly(ethylene glycol) (PEG) blends processed using a twin‐screw extruder, with the aim of enhancing their compatibility. Phthalic anhydride (PAn) and phthalic acid (PAc) were used as potential compatibilizers at different concentrations to improve interfacial interactions between PBT and PEG. Blend morphologies were characterized using scanning electron microscopy, which revealed improved interfacial compatibility and reduced phase separation with the incorporation of small amounts of PAn and PAc. Differential scanning calorimetry analysis indicated changes in the melting temperature (Tm) and glass transition temperature (Tg) of the blends owing to the compatibilizing effects of PAn and PAc. Dynamic mechanical analysis further corroborated the influence of the compatibilizers on the Tg and viscoelastic behavior. Thermogravimetric analysis demonstrated enhanced thermal stability with the addition of either PAn or PAc. Rheological measurements indicated an increase in complex viscosity with increasing compatibilizer content, indicating improved compatibility. The degradation point (Td) of PBT/PEG blend increased from 158 to 200 and 319°C with the incorporation of 5 phr PAn and 2 phr PAc, respectively. Mechanical properties, including tensile strength, Young's modulus, and Izod impact strength, were evaluated. For instance, the tensile strength of PBT/PEG blend was enhanced from 43.5 to 48.7 and 49.7 MPa by incorporating 5 phr PAn and 2 phr PAc, respectively. However, the impact strength of PBT/PEG blend increased from 3.0 to 4.3 and 4.2 kJ/m2 with the addition of 1 phr PAn and 1 phr PAc, respectively. The findings demonstrated that adding 5 phr PAn or 2 phr PAc to the PBT/PEG blends was advantageous, achieving a harmony of performance benefits and compromises. Rheological observations contributed significantly to the mechanical and thermal properties. Overall, the study highlights the significance of utilizing PAn and PAc as effective compatibilizers for enhancing the properties of PBT/PEG blends, making them potential candidates for various applications.

Examination Of Perlite-Polymer Interface Interactions in Polypropylene-Based Composites via Several Compatibilizers

The surface interaction between the polymer and the mineral additive is one of the most significant aspects influencing the efficiency of mineral-filled polymeric composites. In this work, three distinct compatibilizers were introduced to composites based on polypropylene (PP) and perlite to improve interactions between the constituents. On composites comprising 10% expanded perlite content, three different ratios of ethylene vinyl acetate copolymer (EVA), thermoplastic polyurethane elastomer (TPU), and maleic anhydride grafted polypropylene (MA-PP) compatibilizers were employed. Composites were produced using an approach designated melt blending followed by injection molding. The composites containing MA-PP compatibilizer possessed the most outstanding performance, according to the results of mechanical, physical, and dynamic mechanical evaluations and morphological characterizations. The investigated aspects indicated a rise in the composites containing 10 percent compatibilizer with the lowest adding amount, whereas performances declined at high compatibilizer contents. Along with these results, it was determined that the compatibilizers included in the PP/perlite composite system assisted in the fabrication of the composites by promoting the force values and melt flow rates identified during melt mixing. Following the test outcomes, MA-PP performed better than TPU and EVA in terms of compatibilizer efficiency. In general, it has been revealed that the selection of MA-PP compatibilizer in the manufacturing stages would offer benefits in terms of both simplicity of processing and mechanical strength where expanded perlite will be adopted as a natural filler for PP-based composites.

High‐Impact PLA in Compatibilized PLA/PCL Blends: Optimization of Blend Composition and Type and Content of Compatibilizer

AbstractIn this work, the effectiveness of seven commercial compatibilizers is tested in polylactide (PLA)/poly(ε‐caprolactone) (PCL) blends with different compositions to obtain a high‐impact PLA. None of the compatibilizers is effective for 90/10 and 80/20 PLA/PCL compositions, as no improvement of the impact strength is observed. For the 70/30 composition, compatibilizers having glycidyl methacrylate (GMA) and acrylate groups in their structure are proved the most effective, as the morphological change towards co‐continuity induced by them leads to significant impact strength improvements (of ≈345% and 90% with respect to the neat PLA and the noncompatibilized PLA/PCL 70/30 blend, respectively). The 70/30 PLA/PCL composition, as it shows the best balance of properties, and the best compatibilizer (ElvaloyPTW) are chosen to carry out the optimization of the compatibilizer content. It is found that adding 6 phr to the blend results in highly toughened and ductile blends while maintaining a high modulus and yield strength values. Larger compatibilizer contents lead to even higher impact strength values, but the low‐strain mechanical properties are notably reduced. Thus, in this work, a simple and easily scalable method to produce high‐impact PLA is shown, as it implies the compounding of three commercially available components without involving any toxic solvents.

Preparation of self-healing EPDM/ionomer thermoplastic vulcanizates with ionic network for automotive application: Effects of maleic anhydride grafted EPDM as compatibilizer

This work evaluates the effects of maleic anhydride grafted ethylene-propylene-diene rubber (EPDM-g-MAH) on the processing characteristics, compatibility and mechanical properties of EPDM/Ionomer blends. Dynamic vulcanization process was used to fabricate thermoplastic vulcanizates (TPVs) of different compositions using EPDM polymers and high acid (HA60D) or mid acid (MA60D) containing thermoplastic ionomers. The addition of EPDM-g-MAH in EPDM/Ionomer blends had a predominant role as a compatibilizing agent, which affected the processability and properties of the final material. The tensile properties showed significant improvement with increasing the content of compatibilizer in the vulcanizates. The microscopical analysis of fracture surfaces further supported the heterogeneous nature of the blends and compatibility of the polymer phases. The concept was based on a simple ionic crosslinking reaction between carboxyl groups present in the ionomer and zinc oxide (ZnO), where the formation of reversible Zn2+ covalent crosslinks exhibits the self-healing behavior. The combination of blending and ionic cross-linking improved not only mechanical properties but also improved self-healing performance. The self-healing nature of the TPVs has been identified by scratch resistance test, where the ternary blends (EPDM/Ionomer/EPDM-g-MAH) showed 100% healing efficiency of the scratch surface at 89°C for 24 h.

Reactive compatibilization of polypropylene grafted with maleic anhydride and styrene, prepared by a mechanochemical method, for a blend system of biodegradable poly(propylene carbonate)/polypropylene spunbond nonwoven slice

Abstract Poly(propylene carbonate) (PPC)/polypropylene (PP) spunbond nonwoven slice has gained more attention, owing to its excellent properties, such as biodegradability, flexibility, biocompatibility, and CO2 utilization. However, the applications of this green material are limited due to the poor thermodynamic incompatibility between PPC and PP. In this paper, PP grafted with maleic anhydride (MAH) and styrene (St) (PP-g-(MAH-co-St)), prepared by a mechanochemical method and having a grafting percentage G MAH = 1.40 %, was used as a compatibilizer to prepare a biodegradable PPC/compatibilizer/PP composite-spunbond nonwoven slice by melt-blending. The effects of compatibilizer content on the tensile strength, elongation at break, melt flow rate, thermal properties, and micro-morphology of PPC/PP-g-(MAH-co-St)/PP were systematically studied. Furthermore, the mechanism of compatibilization of PP-g-(MAH-co-St) in the PPC/PP spunbond nonwoven composite slice is discussed. The results indicated that this green PP-g-(MAH-co-St) exhibited a clear reactive compatibilization effect. Therefore, it can be considered as a good compatibilizer for the biodegradable PPC/PP spunbond nonwoven slice.

Shape Memory Respirator Mask for Airborne Viruses.

The emergence of COVID-19 has spurred demand for facemasks and prompted many studies aiming to develop masks that provide maximum protection. Filtration capacity and fit define the level of protection a mask can provide, and the fit is in large part determined by face shape and size. Due to differences in face dimensions and shapes, a mask of one size will not be likely to fit all faces. In this work, we examined shape memory polymers (SMPs) for producing facemasks that are able to alter their shape and size to fit every face. Polymer blends with and without additives or compatibilizers were melt-extruded, and their morphology, melting and crystallization behavior, mechanical properties, and shape memory (SM) behavior were characterized. All the blends had phase-separated morphology. The mechanical properties of the SMPs were modified by altering the content of polymers and compatibilizers or additives in the blends. The reversible and fixing phases are determined by the melting transitions. SM behavior is caused by physical interaction at the interface between the two phases in the blend and the crystallization of the reversible phase. The optimal SM blend and printing material for the mask was determined to be a polylactic acid (PLA)/polycaprolactone (PCL) blend with 30% PCL. A 3D-printed respirator mask was manufactured and fitted to several faces after being thermally activated at 65°C. The mask had excellent SM and could be molded and remolded to fit a variety of facial shapes and sizes. The mask also exhibited self-healing and healed from surface scratches.

Crystal and morphology development in immiscible nonpolar polymer blend nanocomposite based on low‐density polyethylene and linear low‐density polyethylene in presence of clay and compatibilizer

AbstractIn this work, polyolefin‐blend/clay nanocomposites based on low‐density polyethylene (LDPE), linear low‐density polyethylene (LLDPE), and organically modified clay (OC) were prepared by melt extrusion. Various grades of maleic anhydride (MA) grafted polyethylene (PE‐g‐MA) were used and examined as compatibilizers in these nanocomposites. Differential scanning calorimetry analysis showed that OC and compatibilizer affect the crystallization behavior of LDPE/LLDPE with different mechanisms. Thermodynamic calculations of wetting coefficient based on interfacial energy between OC, LD, and LL, Morphological characterization based on field emission scanning electron microscopy, X‐ray diffraction, small angles X‐ray scattering, and dynamic rheology measurements revealed that the compatibilizer and OC were localized at the interface of LDPE and LLDPE phases with a preferred tendency toward one phase. Results demonstrated that at a specific amount of OC, there is an optimum compatibilizer concentration to achieve nanodispersed OC and beyond that the compatibilizer causes a structural change in the polymer crystalline morphology. It was also found that the tensile property enhancement of LDPE/LLDPE/OC nanocomposites is closely related to the crystalline structure development made by incorporation of both OC and compatibilizer.

Effects of compositional parameters on morphology and rheological properties of HDPE/PVA blends

AbstractPolymeric blends are relevant for research and industry because of their versatility, being able to accomplish property tailoring with competitive cost and ease to scale up, when compared to the development of in‐reactor new polymers. Blends of thermoplastics, however, might have their morphology and properties altered upon processing, therefore, there is uncertainty to some outputs after melt processing. Therefore, having a fixed morphology that is capable of being further processed without significant changes have industrial and academic value. This work presents a comprehensive study of rheological properties and morphology of a selectively crosslinked blend of polyethylene (HDPE) and poly(vinyl alcohol) (PVA), where the effect of the following parameters are evaluated: dispersed phase (PVA) weight fraction, continuous phase (HDPE) rheological properties, compatibilizer (PE‐g‐MAh) and crosslinking agent (maleic anhydride) content. Overall, melt complex viscosity and elasticity have increased with PVA weight fraction and HDPE viscosity. The compatibilizer content has not severely affected melt rheology, although it influenced blend morphology. Crosslinking agent content affected melt rheology and glass transition temperature in a complex way due to the probable competition of some phenomena (crosslinking and reaction vs reduction of crystallinity degree and H bond attenuation), with little effect over PVA morphology.

Converting flax processing waste into value added biocomposites

Flax fibers have excellent strength and other properties preferable for textile, composites and other applications. In addition to being an important industrial crop, many studies have been reported on the use of flax fibers, flax fabrics and other flax based products as reinforcement for composites. Processing flax fibers into yarns generates considerable (up to 25%) amounts of fibrous and non-fibrous waste which is generally discarded or used for low value applications. Pure flax fiber have current selling price between 6.5 and 7 Euro/kg compared to 0.16–0.19 Euro/kg for the flax waste used in this study which could make the composites highly affordable. To realize the unique properties of flax fibers such as its relatively high strength and add value to the waste, flax processing waste were used as reinforcement for polypropylene (PP) composites. Flax waste was separated into fibrous and non-fibrous (powder) components and combined in various ratios with poly(propylene) as the matrix. A compatibilizer (maleated polypropylene) (MAPP) was used to improve the surface interaction and adhesion between reinforcement and matrix and enhance the properties. Substantial increase in strength and modulus were observed due to the addition of the compatibilizer. A compatibilizer content of 3% was found to be optimum when the tensile strength was highest at 27 MPa and tensile modulus was 1212 MPa. The thermal conductivity and noise insulation properties also showed an improvement from 0.050 to 0.039 W/mK and 0.05–0.35 respectively after the addition of the compatibilizer. Flax-PP composites have properties surpassing that of commercially available medium density particle boards and that of neat PP.

Effect of multi‐epoxy compatibilizers with branched structures on enhancing mechanical and compatibility of PLA/starch composite

AbstractPolylactic acid/starch (PLA/ST) composites are all sustainable origin, have huge cost advantages and degradation tendency to replace petroleum‐based plastics. However, thermodynamic incompatibility between PLA and starch dragged the performance far below expectations. Considering that ethylene glycol diglycidyl ether (EGDE), glycerol triglycidyl ether (GTE), and pentaerythritol glycidyl ether (PGE) have branched multi‐epoxy structure, high epoxy value, and excellent wettability, we firstly explored those materials as compatibilizers in PLA/ST composites. The reactive compatibilization between the epoxy groups on EGDE, GTE, and PGE with the hydroxyl groups on PLA and ST is confirmed by Fourier transform infrared spectroscopy (FT‐IR) analyses. The mechanical properties show that the introduction of only 3 wt% GTE in PLA/ST composites can induce the tensile strength and elongation at break to be increased by 80% and 38%, respectively. The rheological tests indicate that the introduction of only 3 wt% GTE in PLA/ST composites increased the slopes of Han plots from 0.48 to 0.88. Differential scanning calorimetry (DSC) analyses show that the crystallinity increases with the content of compatibilizer, up to 31%. The reduction of the gap between PLA and starch interfaces characterized by Scanning Electron Microscope (SEM) demonstrated that the compatibility of PLA and ST was improved. Furthermore, the effects of EGDE, GTE, and PGE with the same epoxy value but different branch chains on the compatibilization of PLA/ST blends are further discussed. The results show that GTE and PGE with star‐shaped branched structure has a better compatibilization effect on PLA/ST blends than EGDE with linear branched structure.