Compatibilizer Agent Research Articles

Polyethylene-coffee husk eco-composites for production of value-added consumer products

The annual worldwide production of coffee exceeds 10 million tons, and more than 90% of this production is waste, including the husk. On the other hand, plastic consumption increases every year, and sustainable alternatives are necessary to decrease it. This work arises to solve these two problems, and seeks to produce products at an industrial level from polyethylene/coffee husk eco-composites. Both Low Density Polyethylene and High Density Polyethylene were used, and the amounts of coffee husk added as filler were 20 and 40 wt%. The composites were characterized by different morphological, thermal and mechanical techniques. Scanning Electron Microscopy images showed husk particles embedded in the polymer matrix, but with some gaps between the polymer and the filler, because no compatibilizer agent was used. The addition of large amounts of natural filler negatively affected the tensile strength and elongation at break, but increases eco-composites crystallinity, and hence, their Young modulus and hardness. The industrial applicability of the eco-composites was verified through the production of five different consumer products by extrusion and injection processes, using mixtures with 40 wt% coffee husks. All products were obtained without significant defects. If only 3.25 wt% of the polyethylene products produced each year in Colombia did so with the eco-composites developed in this work, all the coffee husk produced in the country would be used, and the emission of about 5.390 million m3 of greenhouse gases would be avoided.

Phenol functionalized high‐density polyethylene as compatibilizer of high‐density polyethylene/graphene nanocomposites toward enhanced mechanical and interfacial adhesion

AbstractIn this work, the methodology to obtain high‐density polyethylene (HDPE) and graphene (G) nanocomposites using phenol‐modified graphene and phenol‐modified HDPE as compatibilizer obtained from the reaction of malleated polyethylene (HDPE‐g‐MA) with phenol, is described. Six different methods were used to obtain these composites, resulting from the combination of melt and solution mixing with three different procedures to functionalize either graphene or HDPE‐g‐MA with phenol. Nanocomposites were characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), wide angle X‐ray diffraction (WAXD), dynamic mechanic analysis (DMA) and tensile properties. The FTIR results evidenced the occurrence of an esterification reaction between HDPE‐g‐MA and phenol groups serving as compatibilizer. The SEM and WAXD results showed that the addition of this compatibilizer agent had a positive effect on graphene dispersion, which promoted greater stiffness in these composite materials, presenting higher storage modulus. In addition, a noticeable enhancement in dimensional stability at high temperatures was observed according to Tan Delta measurements. These results indicated a good interfacial adhesion between graphene and the polymer matrix by using this compatibilizer agent. It was observed that the composites obtained by solution mixing method showed better performance and stronger interfacial adhesions than the composites produced by melt mixing methods. The use of this phenol modified HDPE compatibilizer offers a new option to enhance the final performance of HDPE/graphene composites with better mechanical and thermal properties to be used in materials for various applications, such as automotive industry, electrical and electronics, construction, aerospace, and other engineering applications.

Current State and Challenges of Natural Fibre-Reinforced Polymer Composites as Feeder in FDM-Based 3D Printing.

As one of the fastest-growing additive manufacturing (AM) technologies, fused deposition modelling (FDM) shows great potential in printing natural fibre-reinforced composites (NFRC). However, several challenges, such as low mechanical properties and difficulty in printing, need to be overcome. Therefore, the effort to improve the NFRC for use in AM has been accelerating in recent years. This review attempts to summarise the current approaches of using NFRC as a feeder for AM. The effects of fibre treatments, composite preparation methods and addition of compatibilizer agents were analysed and discussed. Additionally, current methods of producing feeders from NFRCs were reviewed and discussed. Mechanical property of printed part was also dependent on the printing parameters, and thus the effects of printing temperature, layer height, infill and raster angle were discussed, and the best parameters reported by other researchers were identified. Following that, an overview of the mechanical properties of these composites as reported by various researchers was provided. Next, the use of optimisation techniques for NFRCs was discussed and analysed. Lastly, the review provided a critical discussion on the overall topic, identified all research gaps present in the use of NFRC for AM processes, and to overcome future challenges.

Mechanical, physical, thermal and morphological properties of polypropylene composite materials developed with particles of peach and cherry stones

This study aimed to investigate the use of peach stone particles (PSP) and cherry stone particles (CSP) to manufacture composite materials with a polypropylene (PP) matrix.A strong growth of processed fruit industry in Chile in the latter years has generated an increase of solid waste. Some of these residues are stones, stems, peels or others. Conversely, wood plastic composites (WPC) are materials that have been established in the international market, offering new alternatives of use for lignocellulosic by-products of the fruit industry.The novel composites based in peach stones particles and cherry stone particles were compared to a wood plastic composite material manufactured with radiata pine sawdust particles with a polypropylene matrix (WSP-PP). The calorimetric (DSC), thermogravimetric (TGA) and thermomechanical (DMA) analysis, showed that properties of PSP-PP and CSP-PP composite materials were similar to WSP-PP.PSP-PP presented similar mechanical and physical properties to WSP-PP, and CSP-PP the lowest ones. The penetration of the polypropylene matrix into the peach stone particles clearly improved the mechanical anchoring between PSP and PP. This good performance would favor the use of by-products of the fruit industry to elaborate composite materials. The properties of these new composite materials could be improved by adding compatibilizer agents or reinforcement fibers to obtain applications with an enhanced mechanical performance.

The use of recycled low‐density polyethylene films from protective prepreg for the development of nanocomposites with bentonite clay

AbstractPrepreg is a pre‐impregnated composite fiber where a thermoset polymer matrix material is present. Before being used, these materials are kept at low temperatures and have a low‐density polyethylene (LDPE) film for your protection. The increase in the use of structural composites based on prepregs causes an increase in the amount of protective LDPE film. This material is usually discarded or incinerated and can cause great damage to the environment. Thus, the present work aimed to study the feasibility of recycling up to 100% of protective LDPE (rLDPE) to develop blends‐based nanocomposites with rLDPE/virgin LDPE (60/40, 70/30, 80/20, 90/10 and 100/0) with the addition of 5 wt% of compatibilizer agent (maleic anhydride grafted LDPE, LDPE‐g‐MA), and 1 wt% of bentonite (BNT) using a co‐rotational twin‐screw extruder, followed by hot pressing in a hydropneumatic press and die‐cutting. Water absorption test, thermal aging resistance, morphological characterization by scanning electron microscopy, mechanical properties by Izod impact strength and tensile tests, and differential scanning calorimetry were performed. By the results, it was possible to verify the viability of 100% of the recycling of rLDPE. The results showed a good distribution of 1 wt% of BNT in the matrix, better mechanical properties when compared with virgin LDPE. Furthermore, the thermal properties, water absorption test, and thermal aging resistance showed no statistical differences between the samples. These results confirm the effectiveness and the environmental gain in the use of the recycled material.

Tensile and Impact Properties of Rice Husk Filled Ethylene-Acrylic Ester Maleic Anhydride Compatibilized Polypropylene Composites

Rice husk (RH) is an agricultural waste that is gaining importance as fillers for polymers due to its abundant advantages such as light weight, low cost and environmentally friendly. This study investigates the tensile and impact properties of rice husk waste (RH) filled polypropylene (PP) composites with ethylene-acrylic ester maleic anhydride (E-AE-MA) as compatibilizer. The compatibilizer agent is used to improve compatibility between the RH which is hydrophilic and non-polar PP. Tensile test and impact strength test were conducted according to ASTM D638 and ASTM D256 standards. The incorporation of 15 wt% of RH into PP increased the Young's modulus of PP by 28 % but decreased the tensile strength and impact strength by 10 % and 31 % compared to neat PP. The elongation at break was observed to decrease by approximately 4 %. The addition of E-AE-MA at 4 parts per hundred (phr) to the composite increased the impact strength and elongation at break of RH-PP composite by 18 % and 22 % , but decreased the Young's modulus and tensile strength by 18 % and 5 %. The overall results showed that the elongation at break and Young's modulus of the compatibilized RH-PP composite is higher than neat PP, including that E-AE-MA is an effective compatibilizer between RH filler and PP due to its ability to improve adhesion between the two phases.

The Effects of a Compatibilizer for Improving Mechanical Properties on Polymer Matrix Composites

The effect of compatibilizer agent was studied when adding Aluminum fine powder (Al) to reinforce in Polypropylene (PP) by compared between polymer matrix composites (PMCs) and PMCs added Polypropylene graft maleic anhydride (PP-g-MAH).The average particle size of the aluminum fine powder was around 75 μm filled in polypropylene with different proportions of 2.5, 5, 7.5 and 10wt%. PMCs were prepared using the internal mixer. The results found that when the amount of aluminum fine powder increased, the mechanical properties had changed, i.e., tensile strength, and Young’s Modulus increased, while the impact strength and elongation at break decreased. But, when adding compatibilizer 1wt% it was found that the trend of tensile strength, and Young’s Modulus increased that compared with non-compatibilizer, but the impact strength and elongation at break decreased. The part of the morphology of PMCs with non-compatibilizer was found that the particle of aluminum fine powder dispersed in the matrix phase, but there were many microvoids between filler and matrix. But, PMCs with compatibilizer caused the microvoids between filler and matrix to be reduced.

Preparation and evaluation of thermoplastic vulcanizate / organo-modified layered double hydroxide nanocomposite: Statistical modelling and optimization

This study investigates the fabrication and optimization of a novel thermoplastic vulcanizate (TPV) nanocomposite consisting of organo-modified layered double hydroxide (O-LDH) and a polypropylene (PP)/polybutadiene rubber (PBR) base for the first time. O-LDH was prepared by condensation reaction between an aminosilane-modified LDH (Si-LDH) and both maleic-anhydride-grafted-liquid polybutadiene (LPBR-g-MA) and maleic-anhydride-grafted polypropylene (PP-g-MA). A two-component mixture consisting of LPBR-g-MA and PP-g-MA (weight ratio:60/40) (Comp-g-MA) was used as the compatibilizer agent, and bis-(triethoxysilylpropyl)-tetrasulfid (TESPT) was employed as the vulcanizing agent which was activated in the presence of MA. Response surface methodology (RSM) integrated by central composite design (CCD) was utilized to maximize the gel content and minimize the number-averaged rubber particle size (NARPS) of TPV-Nanocomposite by optimizing the amounts of Comp-g-MA, TESPT and O-LDH. The outcomes revealed that increasing the O-LDH and Comp-g-MA up to a certain amount, decreased the size of the vulcanizate PBR domains due to the formation of a strong interface, but it caused an increasing trend for the %gel up to a maximum value. The optimized TPV sample (OTPV) was obtained using 8.2 % Comp-g-MA, 5.8 % O-LDH and 2.5 % TESPT and exhibited 50.4 % of gel content and 135.6 μm of NARPS. OTPV showed superior properties in terms of morphological stabilization, thermal stability and oil-resistance due to the synergistic effect of Comp-g-MA and O-LDH components into the PP/PBR blends.

Gelatinized and nongelatinized starch/pp blends: effect of starch source and carboxylic and incorporation

Due to the environmental impact caused by incorrect disposal and the non-biodegradability of synthetic polymers, the packaging sector seeks renewable raw materials. An alternative is the utilization of natural renewable polymer, such as thermoplastic starch (TPS), mixed with synthetics. However, the chemical incompatibility between these two materials leads to the use of a compatibilizer agent. Even though the compatibilizer effect of carboxylic acid on TPS blends have been studied, the correlation between the carboxylic acid and the starch source has not been investigated yet. Thus, this study focuses on the effects of added carboxylic acids (myristic (C14) and stearic (C18) acid) and the starch sources (corn, cassava, and potato) on the properties and microstructure of blends with TPS/PP (70/30). The results suggested that the compatibilizer effect of acids depends on the starch source and the length of the acid chain, where cassava blends with C14 showed better results. Acid insertion increased tensile strength and deformation at break, but reduced the elastic modulus, indicating a plasticizer effect. This behavior was related to the formation of amylose and lipid complexes (endogenous or added) during heating. Torque reduction and Tg displacement were also observed for acid blends. The SEM images showed two different morphological dispersions and a non-gelatinization effect due to the acid insertion. Results suggested that acids act differently according to the starch source.

Effectiveness of the preparation of maleic anhydride grafted poly (lactic acid) by reactive processing for poly (lactic acid)/carbon nanotubes nanocomposites

AbstractAn effective strategy to increase the properties of poly (lactic acid) (PLA) is the addition of carbon nanotubes (CNT). In this work, aiming to improve the surface adhesion of PLA and CNT a new compatibilizer agent was prepared by reactive processing, PLA grafted maleic anhydride (PLA‐g‐MA) using benzoyl peroxide and maleic anhydride. The effectiveness of the PLA‐g‐MA as a compatibilizer agent was verified for PLA/PLA‐g‐MA/CNT nanocomposites. PLA and PLA‐g‐MA samples were characterized by Fourier transform infrared spectroscopy (FT‐IR) to confirm the grafting reaction of maleic anhydride on PLA chains and by rheological analysis to prove the changes in the matrix PLA after the graphitization reaction. Thermal (differential scanning calorimetry and thermogravimetric analysis), mechanical tests (Izod impact strength and tensile test), and morphological characterization were used to verify the effect of the compatibilizer agent. The preparation of PLA‐g‐MA by reactive extrusion processing proved satisfactory and the nanocomposites presented good thermal and mechanical properties. The addition of the PLA‐g‐MA also contributed to the greater distribution of CNT and can be used as an alternative for the production of PLA/CNT nanocomposites.

Processing and characterization of polypropylene (PP)/ethylene–vinyl acetate (EVA) blend-based glassy carbon (GC) composites

Polypropylene (PP)/ethylene–vinyl acetate (EVA) (60/40) blends-based glassy carbon (GC) composites with different contents of GC (0.1 to 5 wt%) were melting processed in a twin-screw extruder and the thermal, mechanical, electrical and morphological properties were evaluated to verify the effectiveness of the addition of GC as filler. Moreover, the effect of the addition of maleic anhydride grafted polypropylene (PP-g-MA) as a compatibilizer agent was also verified. The composites presented dispersed phase morphology with preferential localization of GC on interfacial regions and into the EVA phase. The mechanical properties were improved with the addition of PP-g-MA as a compatibilizer agent for the blend and the addition of GC had little influence on these properties. The results obtained from thermal properties revealed that the GC contributes to the increase in the degree of crystallinity and thermal stability of the composites. The addition of 0.1 wt% of GC increased the elastic modulus and the ultimate tensile strength without loss in the impact strength when compared to the compatibilized blend. The addition of GC increases a decade of magnitude in the electrical conductivity of the PP/EVA blends.

Graphene Oxide and Vermiculite Clay Combinations to Produce Enhanced Flame Retardant Polypropylene Composite with Low Magnesium Hydroxide Loading

AbstractThe effect of graphene oxide (GO) functionalized with 3‐amino‐propyl‐triethoxy‐silane(APTS), organo‐vermiculite(OVMT), and magnesium hydroxide (MH) combinations on mechanical, thermal, and flame retardant (FR) properties of polypropylene (PP) was studied. GO was obtained via a slight modification of the Hummers method and then chemically surface functionalized with APTS. VMT clay was modified with maleic anhydride (MA) via a chemical reaction with acetic acid to increase its inter‐laminar spacing. The results of Fourier‐transform infrared analysis, X‐ray diffraction, and transmission electron microscopy demonstrated that APTS had been successfully attached to the GO and that VMT was modified with MA. Subsequently, each functionalized filler was incorporated in combination with MH to the flame‐retardant‐polypropylene system. The performance of PP composites with each filler as well as with their combinations, including a reduced “30 wt% of MH” were compared with the reference PP composite with 55 wt% of MH as the only FR additive. PP grafted with MA (PP‐gMA) and PP grafted with amine‐alcohol(PP‐gDMAE) were used as compatibilizer agents between each filler and the polymer matrix. The results obtained confirmed a better mechanical and FR performance when using PP‐gDMAE. Composites with 30 wt% MH combined with very low contents of GO (0.5 and 1.0 wt%) showed improved FR properties, similar to the reference sample, with an evident reduction in peak of the heat release rate (pHRR) and total heat release and increased limiting oxygen index (LOI) values. The combination of MH and GO showed the best FR and mechanical properties: LOI of 22.5% and pHRR of 540 kW/m2 which were very similar to the reference sample. In addition, PP‐gDMAE improved the OVMT exfoliation with a slight increase in the intergallery spacing but OVMT and modified GO combinations did not significantly improve the FR and mechanical properties compared with the effect of MH and modified GO combinations. The combination of MH and modified GO makes it possible to reduce the total MH filler content from 55 to 30 wt% to accomplish the FR requirements and with enhanced mechanical properties. This filler combination promoted the formation of a continuous, intact residual char layer on the PP surface, which acts as an insulating barrier to protect the base material. These filler combinations offer an option to meet the FR properties using halogen‐free FR with better mechanical properties.

Effect of Carbon Nanotubes (CNT) Functionalization and Maleic Anhydride-Grafted Poly(trimethylene terephthalate) (PTT-g-MA) on the Preparation of Antistatic Packages of PTT/CNT Nanocomposites

Electronic devices require the use of antistatic packing to prevent electrostatic discharge during their storage or transport. Poly (trimethylene terephthalate) (PTT) is a polyester with excellent properties and can be a good candidate for this application. To make this insulating polymer an extrinsic conductor, carbon nanotubes (CNT) can be added to reduce the electrical resistivity of the nanocomposites. In order to facilitate the CNT distribution on polymeric matrix, it was proposed a chemical functionalization using nitric acid for the creation of functional groups on its surface. Moreover, the PTT matrix was modified with a compatibilizer agent based on maleic anhydride grafted PTT (PTT-g-MA), to improve interfacial adhesion between the nanofiller and matrix. In this work, nanocomposites based on PTT/PTT-g-MA/CNT were prepared by extrusion process, with 0.5 wt% and 1.0 wt% of CNT and functionalized CNT. CNT was characterized by stability dispersion in water, Raman spectroscopy, FTIR and XPS analysis, which prove the success of functionalization. The nanocomposites were evaluated by thermal analysis, tensile tests, electrical conductivity, and morphological analysis. The CNT functionalization and the addition of PTT-g-MA increased the dispersion and distribution of CNT in the PTT matrix. The electrical properties show that this material can be used as an antistatic packaging.

Tribological properties of compatabilizer and graphene oxide-filled polypropylene nanocomposites

Effect of maleic-anhydride-grafted-polypropylene (PP-g-MA) and graphene oxide (GO) addition on the tribological properties of polypropylene (PP) nanocomposites were investigated in this study. Graphene oxides with different levels (0.05 and 0.15 wt%) were used as reinforcing filler for PP nanocomposites. Maleic-anhydride-grafted-polypropylene (3 wt%) was added as a compatibilizer agent to increase the interaction between the GO and PP matrix. GO-filled PP nanocomposites with and without PP-g-MA were produced by a twin-screw extruder followed by injection moulding. Wear tests were carried out under dry sliding conditions against AISI 1040 steel disc using a pin-on-disc device at 0.4–1.6$$\hbox { m s}^{-1}$$ sliding speed and 10–40 N loads. The tribological test results showed that the coefficient of friction and wear rate of PP nanocomposites increased with applied loads and sliding speeds. The coefficient of friction decreased by 8.2, 14.2, 37.3 and 74.7% under $$1.2\hbox { m s}^{-1}$$ sliding speed and 40 N load with the addition of PP-g-MA and GO to the PP nanocomposites. The wear rate of PP and its nanocomposites was $$10^{-13}\hbox { m}^{2}\hbox { N}^{-1}$$. The minimum wear rate was obtained for 0.15 wt% GO and 3 wt% PP-g-MA-filled PP nanocomposites with a value of $$5.7537\hbox {E}^{-14}\hbox { m}^{2}\hbox { N}^{-1}$$ at $$0.4\hbox {m s}^{-1}$$ sliding speed and 10 N load in this study.

A simple mixing method for polyamide 12/attapulgite nanocomposites: structural and mechanical characterization

In this work, the attapulgite (ATP) was used as a promising mineral clay to prepare polyamide 12 (PA12) matrix polymer nanocomposites. ATP has a relatively low cost compared to other nanoclays and is a very abundant raw material in the northeast region of Brazil. The ATP was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy and field emission gun scanning electron microscopy (FEG-SEM). The PA12/ATP nanocomposites with 0, 1, 2.5, 5, 7.5 and 10 wt% of ATP were prepared using a simple blending method in a high-speed thermokinetic homogenizer (3000 rpm) in which the melting of the PA12 and the mixture with ATP occurred by friction, followed by hot pressing and stamping of the specimens. The nanocomposites were characterized by mechanical properties, the degree of crystallinity and crystallite size were calculated by XRD, and the morphological characteristics were observed by SEM. The addition of ATP in the PA12 matrix increased the modulus of elasticity, hardness, degree of crystallinity and the apparent crystallite size of the nanocomposites. The addition of up to 5 wt% of ATP increased tensile strength and deformation at break; for higher concentrations, the dispersion was not efficient. A major advantage of using ATP as a reinforcement agent for PA12 is the low cost of this material plus the great interaction with PA12 which can dispense the use of compatibilizer agents and/or surface modification in the ATP, making it a potential material to extend PA12’s range of applications.

Influence of the morphology and viscoelasticity on the thermomechanical properties of poly(lactic acid)/thermoplastic polyurethane blends compatibilized with ethylene‐ester copolymer

ABSTRACTViscoelastic, interfacial properties, and morphological data were employed to predict the thermal and mechanical properties of compatibilized poly(lactic acid) (PLA)/thermoplastic polyurethane (TPU) blends. The combination of interfacial thickness measured by contact angle and entanglement density determined by dynamical mechanical analysis analyze data was employed to evaluate the mechanical behavior of PLA/TPU blends with and without ethylene‐butyl acrylate‐glycidyl methacrylate (EBG) compatibilization agent. The PLA/TPU blend (70/30 wt %) was prepared in a Haake internal mixer at 190 °C and compatibilized with different contents of EBG. The evaluation of the interfacial properties revealed an increase in the interfacial layer thickness of the PLA/TPU blend with EBG. The scanning electronic microscopy images showed a drastic reduction in the size of the dispersed phase by increasing the compatibilizer agent EBG content in the blend. The compatibilization of the PLA/TPU blends improved both the Izod impact strength and yield stress by 38 and 33%, respectively, in comparison with neat PLA/TPU blend. The addition of EBG into PLA/TPU blends significantly increased the entanglement density and the PLA toughening but resulted in a decrease of PLA deformation at break. The PLA and TPU glass transitions were affected by the EBG, suggesting that the PLA and TPU domains were partially miscible. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48926.

Reactive processing of maleic anhydride-grafted ABS and its compatibilizing effect on PC/ABS blends

Abstract Polymer compatibilizer agents are crucial for industrial materials development. Compatibilizer agents may be prepared by melt-grafting in the reactive extrusion process which is cheaper and environmentally friendly. Maleic anhydride-grafted acrylonitrile-butadiene-styrene (ABS-g-MA) has emerged as a relevant compatibilizer agent for immiscible blends, like polycarbonate (PC)/ABS. In this work, ABS-g-MA was prepared by a simple reactive extrusion process using ABS, maleic anhydride (MA) and benzoyl peroxide (BPO). The MA:BPO ratios of 1:0.5 and 1:1 varying the content of MA by 1, 2 and 5 wt% were investigated. The grafting reaction was confirmed through Fourier transform infrared spectroscopy (FT-IR), grafted degree (GD%), thermal and rheological analysis. The effectiveness of the compatibilizer agent was evaluated in PC/ABS blends (70/30 and 85/15 blend ratios). The addition of 5 wt% of ABS-g-MA (5 MA:2.5 BPO) in the PC/ABS blends promoted an expressive reduction of ABS domain sizes and better dispersion in the PC matrix.

Compatibilization of natural rubber–polypropylene thermoplastic elastomer blend

The effects of the addition of epoxidized natural rubber/maleic anhydride-grafted polypropylene blend as a compatibilizing agent (CA) on the properties of natural rubber (NR)/polypropylene (PP) thermoplastic elastomer blend were studied. The blends were prepared in the molten state at 180°C using a Brabender Plasticorder at a rotor speed of 60 r min−1. Evidence of compatibilization was obtained from the Brabender plastograms and from the mechanical properties results as well as the morphological analysis. It was found that the addition of the CA at different contents resulted in an increase of the tensile strength and Young’s modulus and a decrease of the elongation at break. It was also found that the melting temperature remained unchanged, the % crystallinity decreased, but the thermal stability was not affected. The morphology revealed a more homogeneous distribution of the dispersed PP phase for the CA-containing systems compared to the control NR/PP blend. These effects were attributed to the interactions that developed with the blend constituents through the functional groups of the CA.

Protective Low-Density Polyethylene Residues from Prepreg for the Development of New Nanocomposites with Montmorillonite: Recycling and Characterization

A sustainable alternative to the destination of polyethylene (PE) residue from the prepreg package was established. This work intends to develop nanocomposites for packaging containing neat low-density polyethylene (LDPE), a compatibilizer agent (maleic anhydride grafted-LDPE, LDPE-g-MA), recycled LDPE obtained from the protective films of prepreg (rLDPE) and montmorillonite (MMT). The rLDPE, from the prepreg shield, has a primary role during the transport and storage of prepreg, which can be composed of epoxy resin and carbon fiber or glass fiber. However, this rLDPE is withdrawn and discarded, besides, it is estimated that tons of this material are discarded monthly by the company Alltec Materiais Compostos Ltd. (São José dos Campos-SP, Brazil). Due to several factors, including the lack of technology for recycling, the majority of this material is incinerated. In this context, this work presents a technical and ecologically viable alternative for the use of this discarded material. Nanocomposites of LDPE/rLDPE blends and montmorillonite (MMT) with different contents (0.0, 1.0, and 3.0 wt%) and with the addition of compatibilizer agent (LDPE-g-MA) were prepared by extrusion process. Test specimens were obtained by hot pressing in a hydropneumatic press followed by die-cutting. The nanocomposites produced using rLDPE presented good mechanical, thermal, and morphological properties, being the ideal concentration of 1 wt% MMT. Thus, the results obtained confirmed the viability of recycling LDPE from the prepreg package which contributes to the reduction of waste and the use of this material in technological applications.

Multiscale Characterization of a Wood-Based Biocrude as a Green Compatibilizing Agent for High-Impact Polystyrene/Halloysite Nanotube Nanocomposites.

This paper investigates merits of using a wood-based biocrude (WB) from aspen wood to improve the compatibility of halloysite nanotubes (HNTs) with high-impact polystyrene to develop nanocomposites with desirable thermomechanical properties. Morphological, thermal, and rheological properties of the resulting nanocomposite are used as indicators of the compatibility and dispersion of the modified HNT within the polymer matrix. Computational modeling using density functional theory is used along with laboratory experiments to provide a multiscale characterization of the above biocrude and nanocomposites. Studies performed through dispersion-corrected density functional theory calculations show that the active functional groups of WB molecules including carbonyl, hydroxyl, and carboxylic interact with the HNT surface, while their aromatic tails interact with the phenyl groups of the polystyrene. Furthermore, the studies reveal how WB molecules act as bridges between the hydrophobic polymer and the hydrophilic clay improving the compatibility. The latter was confirmed by Hansen solubility parameters and was evidenced in improved dispersion of clay within the polystyrene matrix observed by microscopy. Rheological and thermal analyses of the modified HNT and nanocomposites showed physical interactions of WB with HNT surface as well as interactions between the WB-modified HNT and the high-impact polystyrene. The WB was found to be a strong candidate as a green compatibilizing agent for HNT in high-impact polystyrene. The study results can provide insights for formulators and manufacturers looking for green compatibilizing agents in conventional nanocomposites for construction and manufacturing applications.