Melt Blending Process Research Articles

Molding blends of silicone polymer / polypropylene with durable resistant to extreme conditions based on migration and compatibility of molecular chains

Because of low surface energy, silicone polymers would easily peel off from polypropylene (PP) substrate as hydrophobic coatings and they are incompatible with PP in melt-blending process as well. Therefore, ethylene polymers modified with both silicone and alkane side-groups were prepared by nucleophilic substitution in this work. It was confirmed that these prepared polymers could migrate and aggregate to the surface of the blends at that melting temperature when blended with PP due to the low surface energy and high entropy of silicone side groups. Meanwhile, chain entanglement was achieved between alky side-groups of silicone polymers and polymer chain of PP by melt-blending process, so that the compatibility of the blends was improved and the bonding force of two polymers increased simultaneously. Accordingly, molding blends with stable and durable hydrophobility were successfully gained based on migration of silicone and entanglement of alkane and PP. It’s noticeable that the water contact angle of the blend remained to be about 106° from 113°, even soaking in acid (pH = 1) and alkali (pH = 14) solutions, deionized water and anhydrous ethanol, or under multiple strong frictions. This will provide a facile and effective strategy to endow general materials with durable antifouling properties directly by injection molding without additional coating.

Polypropylene Blends with Durable Hydrophobicity and Enhanced Mechanical Properties Based on POSS and Alkane Modified Polypentafluorophenyl Methacrylate.

Durable functionalization on polypropylene (PP) surfaces is always a key problem to besolved. Coatings with low surface energy peel off easily especially under extreme conditions, owing to their weak adhesion. In this paper, side groups of both polyhedral oligomeric silsesquioxane (POSS) and alkane are grafted to polypentafluorophenyl methacrylate (PFP), and then PP blends with these side-group modified PFP are obtained through a melt-blending process. It is found that POSS can result in surface segregation and provide hydrophobicity in blends. Microfibers are formed because of the orientation effect during the tensile testing, which furtherly promotes mechanical strength. Significantly, alkaneside-groups can be entangled with PP segments, which brings about cross linking. Therefore, with crosslinking and synchronous orientation of POSS, the elongation at the break of blends is greatly increased up to 974%. The final blend demonstrates quite durable hydrophobicity under many extreme conditions, such as repeated tape peeling, ultrasonic washing, strong friction, and soaking in strong acid (pH = 1), strong alkali (pH = 14) and alcohol. The heat and UV resistance of the blend are also obviously improved. This study will develop anovel and facile strategy to endow PP with durable hydrophobicity as well as greatly enhanced mechanical properties.

A comparison of physical, morphological, and mechanical properties of bio‐polyester hybrid nanocomposites

AbstractIt is imperative to improve the physical, morphological, and mechanical properties of biodegradable polymers like polylactic acid (PLA), poly (butylene adipate‐co‐terephthalate) (PBAT), and polycaprolactone (PCL) in order to employ them on a larger scale. The development of hybrid nanocomposite materials using nano inclusions can improve desired qualities. Here we introduced an interactive nano reinforcement approach to improve the properties by combining graphene oxide (GO) and carboxyl functionalized MWCNT (f‐MWCNT), to provide for their chemical bonding for synergic reinforcement. A constant filler 2 wt.% was added to the biopolyesters by melt blending process and examined the different physical properties like water absorption, intrinsic viscosity, and hardness. To completely evaluate the functionalization of the nanofillers, wide‐angle X‐ray diffraction (WAXD), Raman spectroscopy and Fourier transform infrared radiation (FTIR) analyses were used. The paired nanoparticles and polymer matrix appear to mix well together, as shown by electron microscopy, which also reveals good dispersion and the creation of a reinforcing network microstructure across the matrix layer. A thorough analysis of the results showed that effective stress transmission, delaying the start of faults and generating microcracks, and dissipating additional mechanical energy all contributed to efficient hybrid network formation, which improved the mechanical properties of hybrid filler nanocomposites except some nanocomposites. These findings offer a viable technique for chemically altering biodegradable polymers, like PLA, PBAT, and PCL for use in biomedical, wastewater management, and agricultural applications.

Morphological, mechanical and biological assessment of PCL/pristine graphene scaffolds for bone regeneration

Scaffolds are physical substrates for cell attachment, proliferation, and differentiation, ultimately leading to the regeneration of tissues. They must be designed according to specific biomechanical requirements such as mechanical properties, surface characteristics, biodegradability, biocompatibility, and porosity. The optimal design of a scaffold for a specific tissue strongly depends on both materials and manufacturing processes. Polymeric scaffolds reinforced with electro-active particles could play a key role in tissue engineering by modulating cell proliferation and differentiation. This paper investigates the use of an extrusion additive manufacturing system to produce PCL/pristine graphene scaffolds for bone tissue applications. PCL/pristine graphene blends were prepared using a melt blending process. Scaffolds with regular and reproducible architecture were produced with different concentrations of pristine graphene. Scaffolds were evaluated from morphological, mechanical, and biological view. The results suggest that the addition of pristine graphene improves the mechanical performance of the scaffolds, reduces the hydrophobicity, and improves cell viability and proliferation.

Easily manufacture lightweight EPDM/POE/KB foam with high electromagnetic shielding efficiency and high absorption coefficient through chemical foaming

Utilizing foam-structured composite materials for electromagnetic shielding offers several advantages, including lightweight properties, low filler load, and a high absorption coefficient. However, their application in electromagnetic shielding is often limited by relatively lower mechanical performance. This study employed melt blending and chemical foaming processes to fabricate a lightweight EPDM/POE/KB composite foam with favorable mechanical characteristics, heat resistance, and electromagnetic absorbing performance. Significantly, the foam, with a density of 0.195 g/cm³, demonstrates an absorption-dominated shielding mechanism (absorption coefficient of 0.71) and good electromagnetic shielding performance of 20.57 dB in the X-band. The honeycomb structure formed within the material contributes to the multiple reflections of electromagnetic waves. Additionally, the composite foam exhibits excellent flexibility, with a fracture elongation greater than 150 %, alongside tensile and compressive strengths of 1.46 MPa and 0.92 MPa, respectively, demonstrating satisfactory mechanical performance. Furthermore, the composite foam also possesses good thermal stability. The study provides a low-cost and effective method for preparing lightweight, high-absorption coefficient, and excellent mechanical performance electromagnetic shielding foam.

The effect of polylactic acid-based blend films modified with various biodegradable polymers on the preservation of strawberries

Polylactic acid (PLA) has garnered much attention in the field of fruit and vegetable packaging. Despite its poor flexibility and water resistance, PLA film faces challenges in being used for strawberry storage and freshness preservation due to its inability to maintain flavor quality. In this study, a series of PLA-based modified films was produced by melt blending and extrusion cast processing with PLA as the main component, along with flexible biodegradable polyesters or polycarbonate as the secondary component. First, five different biodegradable polymers were used to investigate the effect of the flexibility and barrier properties of different dispersed phases on the morphology, mechanical properties, and water vapor barrier of PLA-based blend films. Next, the impact on the freshness of strawberries was assessed through examination of fruit color and weight, as well as the levels of O2 and CO2 in the packaging bags. The results showed that the size of the dispersed phase and interfacial bonding with PLA were the key factors determining the mechanical and barrier properties of the blend films. The PLA-polycaprolactone (PCL) blend showed the best compatibility among them, with PCL having the smallest dispersion size (D=0.58 µm), higher toughness than the other four PLA blends, and greater enhancement of PLA. Additionally, it exhibited a similar rate of quality loss in strawberry preservation compared to commercial PE. As a result, the color and luster were more completely preserved. The results of this study may help the future development of degradable plastics, to reduce environmental pollution.

In Situ Formation of Compound Eye-like SAN-OSB Composite Microspheres by Melt-Blending Method: Enhancing Multiple-Scattering Effect.

The preparation of novel structures of light-diffusing particles is currently a research focus in the field of light-diffusing materials. This study, conducted by the common melt-blending process, controlled thermodynamic and kinetic factors to distribute smaller-sized organic silica bead (OSB) particles at the interface between a polycarbonate (PC) matrix and spherical island-phase styrene-acrylonitrile copolymer (SAN) for the in situ formation of compound eye-like microspheres with SAN as "large eyes" and OSBs as "small eyes". Through the multiple-scattering effects of these compound eye-like microspheres, these light-diffusing materials significantly improved the haze, scattering range, and light-shielding capabilities while maintaining high transmittance. Specifically, the PC/SAN-OSB light-scattering materials achieved a haze of 100% with an OSB content of only 0.17%, maintaining a transmittance of 88%. Compared with the PC/OSB system with the same level of haze, the addition of OSB was reduced by 88%. Therefore, this study achieved exceptionally effective light-diffusing materials through a simple, environmentally friendly, and low-cost preparation method, suitable for the scalable production of light-diffusing materials in new display and lighting fields.

Enhanced High-Performance iPP/TPU/MWCNT Nanocomposite for Electromagnetic Interference Shielding.

The rapid development of electronic communication technology has led to an undeniable issue of electromagnetic pollution, prompting widespread attention from researchers to the study of electromagnetic shielding materials. Herein, a simple and feasible method of melt blending was applied to prepare iPP/TPU/MWCNT nanocomposites with excellent electromagnetic shielding performance. The addition of maleic anhydride-grafted polypropylene (PP-g-MAH) effectively improved the interface compatibility of iPP and TPU. A double continuous structure within the matrix was achieved by controlling the iPP/TPU ratio at 4:6, while the incorporation of multi-walled carbon nanotubes endowed the composites with improved electromagnetic shielding properties. Furthermore, by regulating the addition sequence of raw materials during the melt-blending process, a selective distribution of carbon nanotubes in the TPU matrix was achieved, thereby constructing interconnected conductive networks within the composites, significantly enhancing the electromagnetic shielding performance of iPP/TPU/MWCNTs, which achieved a maximum EMI shielding efficiency of 37.8 dB at an iPP/TPU ratio of 4:6 and an MWCNT concentration of 10 wt.%.

Customized Extrusion Nozzle Assisted Robust Nylon 6/MWCNT Nanocomposite Based Triboelectric Nanogenerators for Advanced Smart Wearables

To meet the growing demand for durable, tough, and electrically conductive polymer nanocomposites driven by the rise of smart devices, e-textiles, wearables, and advanced structures, this study offers a systematic approach to fabricating highly robust Nylon 6/multi-walled carbon nanotubes (MWCNTs) nanocomposite films and fibers. The robustness of the nanocomposite is achieved through a simple straightforward approach involving the selective surface functionalization of MWCNTs with oxygen plasma-assisted tetraethylenepentamine grafting (O2T-MWCNTs) and melt-blending these MWCNTs with Nylon 6 under optimized conditions. The mixture is then processed through a specially designed narrow convergent nozzle attached to the extruder die. The die facilitates the alignment of the CNTs into the matrix in the flow direction and increases the composite strength. The incorporation of just 1 wt% of O2T-MWCNTs into Nylon 6 results in a nanocomposite with a remarkable enhancement, demonstrating a 93.25 % increase in tensile strength (T.S.), a 50.47 % increase in Young’s Modulus (E), and an outstanding 136 % increase in elongation at the break (ε) compared to neat Nylon 6, surpassing contemporary benchmarks. Importantly, this method yields a nanocomposite ∼ 30.2 % stronger than the conventional melt-blending process without a nozzle. When fabricating a triboelectric nanogenerator (TENG) with the nanocomposite, exceptional performance was observed, with an output voltage of 105.7 V, a current of 10.55 μA, and a power density of 465 mW/m2, surpassing many reported values. Moreover, the TENG displays highly stable performance through 20,000 cycles of continuous compression. The nanogenerator also exhibited outstanding capability in harvesting mechanical energy from body movements, as demonstrated by lighting various LEDs and small electronics.

Valorisation of Agricultural Residue Bio-Mass Date Palm Fibre in Dry-Blended Polycaprolactone (PCL) Bio-Composites for Sustainable Packaging Applications

Abstract Purpose This study experimentally developed and characterised dry-blended Polycaprolactone (PCL)/date palm fibre biodegradable composites for sustainable packaging applications. Date palm fibres are collected from date palm trees as by-products or waste materials. They will be valorised in bio-composite application to promote fibre-based sustainable packaging items over their non-biodegradable synthetic polymer based conventional packaging products. In the dry-blending process, fibre and polymer are mixed with a shear mixer, while, in a melt-blending process, an extruder is used to extrude fibre/polymer blends after applying heating and high shear pressure to melt and mix polymer with fibres. Dry-blending process offers many comparative advantages, such as less equipment, steps, cost, process degradation, energy consumption and hence, lower harmful environmental emissions; while, a proper fibre/polymer mixing is a challenge and it needs to be achieved properly in this process. Therefore, it is important to understand the effects of dry-blending process on manufacturing of PCL/date palm fibre bio-composites for packaging applications, before promoting the dry-blending as a suitable alternative to the melt-blending process. Methods Short chopped fibres were grinded as powders and dry-blended at a ratio of (0 − 10%) (w/w) with PCL polymer using hand and a shear mixer for 30 min, following a compression moulding process to produce bio-composite samples. Tensile, water contact angle, SEM, TGA, DSC and DMA tests and analysis were conducted. The dry-blended PCL/date palm fibre composites’ properties were compared with reported melt-blended samples’ results found in literature. Results Dry-blended samples showed an increase in tensile modulus values (up-to 20%) with fibre inclusion and these values were found close to the melt-blended samples in the literature. Tensile strength and strain values were reduced which could be related to the poor fibre/polymer interface. Fibre addition affected the thermal, thermo-mechanical and crystallisation processes in PCL polymer matrix. Conclusion Dry-blending is capable of producing bio-composites with a very comparable properties to melt-blended counterparts, although a more details study is needed to conduct in future. The results of this study, could be used carefully to design dry-blended PCL/date palm fibre bio-composites for possible packaging applications. The irregular fibre distribution in dry-blended samples could be improved in different ways which should be investigated in future. Graphical Abstract

Synergistic Effect of PBz/Epoxy/PCLA Composite Films with Improved Thermal Properties

Polybenzoxazines (PBzs) are advanced forms of phenolic resins that possess many attractive properties, including thermally induced self-curing polymerization, which produces void-free polymer products without any by-product formation. They also possess a high Tg (glass transition temperature) and thermal stability, but the produced materials are brittle in nature, due to which the final form of their application is very difficult. Hence, in this paper, an attempt has been made to overcome the brittleness of PBz by blending it with epoxy and ε-caprolactam (CPLA) to produce free-standing PBz/Epoxy/PCLA (polycaprolactam) films. The curing process between the three components (i.e., Bzo, epoxy, and caprolactam) was monitored using differential scanning calorimetric (DSC) analysis. The results show that there is no appreciable shift in curing the exotherm observed, except a slight shift in the curing process. However, the heat liberated during the exotherm (ΔH) decreases drastically from 121 to 84 J/g, indicating that the content of benzoxazine is very important as it is involved in the polymerization process through oxazine ring-opening. The morphological studies analyzed using SEM and AFM analyses indicate that there was no observable phase separation up to 30 wt.% of CPLA loading, whereas a higher CPLA content of 50 wt.% causes agglomeration and leads to distinctive phase separation. Moreover, the thermal stability of the composite film, PBz/Epoxy/PCLA30, is also increased with a 10% degradation temperature, T10, of 438 °C, when compared with an PBz/Epoxy film. From the obtained results, it is evident that the formation of a composite film through the melt blending process could produce a tough and thermally stable film without sacrificing individual properties.

Effect of polycarbodiimide, epoxy chain extenders and tannic acid on the hydrolysis and UV resistance of polylactic acid

Polylactic acid (PLA) possesses characteristics such as biodegradability, ease of processing, and environmental friendliness, making it an ideal alternative to petroleum-based polymers. However, PLA has drawbacks such as susceptibility to hydrolysis and sensitivity to ultraviolet (UV) light, limiting its application in certain areas. In this study, poly(carbazole diimide) (PCDI) and the epoxy chain extender Joncryl ADR4468 (CE) were employed as a synergistic anti-hydrolysis agent for PLA, and tannic acid (TA) was used as a UV-resistant agent. A melt-blending process was employed to prepare PLA composite materials with enhanced resistance to both hydrolysis and UV radiation. The results indicate that the addition of PCDI-TA-CE significantly improved the performance of PLA. After 8 h of hydrolysis at 80 °C, the tensile strength of PLA increased from 38.31 MPa for pure PLA to 77.69 MPa with the incorporation of PCDI-TA-CE. The elongation at break increased from 0.6% to 1.5%, and the Ultraviolet Protection Factor (UPF) value elevated from 3.19 for pure PLA to 503.46.This demonstrates that PCDI, CE, and TA can effectively enhance the anti-hydrolysis and UV resistance properties of PLA.

Fractionated lignin as a green compatibilizer to improve the compatibility of poly (butylene adipate-co-terephthalate) /polylactic acid composites

Blending poly (butylene adipate-co-terephthalate) (PBAT) and polylactic acid (PLA) is a cost-effective strategy to obtain biodegradable plastic with complementary properties. However, the incompatibility between PBAT and PLA is a great challenge for fabricating high-performance composite films. Herein, the ethyl acetate fractionated lignin with the small glass transition temperature and low molecular weight was achieved and incorporated into the PBAT/PLA composite as a compatibilizer. The fractionated lignin can be uniformly dispersed within the PBAT/PLA matrix through a melt blending process and interact with the molecular chain of PBAT and PLA as a bonding bridge, which enhances the intermolecular interactions and reduces the interfacial tension of PBAT/PLA. By adding fractionated lignin, the tensile strength of the PBAT/PLA composite increased by 35.4 % and the yield strength increased by 37.7 %. Owing to lignin, the composite films possessed the ultraviolet shielding function and exhibited better water vapor barrier properties (1.73 ± 0.08 × 10−13 g·cm/cm2·s·Pa). This work conclusively demonstrated that fractionated lignin can be used as a green compatibilizer and a low-cost functional filler for PBAT/PLA materials, and provides guidance for the application of lignin in biodegradable plastics.

Preparation and characterization of poly(vinyl alcohol)/poly(lactic acid) blends containing bio‐based plasticizers

AbstractThe bio‐based plasticizers‐glycerol and lactic acid were used to plasticize and compatibilize PVA/PLA blends during melt blending process. It was confirmed that lactic acid significantly improved the compatibility between glycerol‐plasticized PVA and PLA. Compared with pure PVA, the melting and crystallization temperatures and crystallinities decreased but the crystal form of PVA in the blends was not changed. The thermal stabilities of PVA/glycerol (G)/lactic acid (L)/PLA blends were better than PVA/G/PLA blends. Compared to PVA/G/PLA blends, the tensile and tear strength of PVA/G/L/PLA blends were improved, however, elongation at break decreased. The water absorptions and water vapor permeances of the blends decreased with the addition of hydrophobic PLA, but they increased by incorporation of hygroscopic lactic acid. The surface resistivities of the blends augmented in combination with PLA but declined by adding lactic acid. The melt flow rates of PVA/G/PLA blends were better than PVA/G/L/PLA blends because lactic acid enhanced the interactions among the components. After the addition of lactic acid, the transmittances of the blends increased due to the refined dispersed phases by the compatibilization. The compatibility between the components was predicated by Hansen solubility parameters. These blends showed potential as a novel barrier material for food and medicine packages.Highlights PVA, glycerol, and PLA blends were compatibilized by lactic acid. The melting temperatures decreased with addition of glycerol and lactic acid. The tensile and tear strengths were enhanced with addition of PLA and lactic acid. The hydrophobicity, melt fluidity, and surface resistivity were improved by PLA.

Biodegradable Nanocomposites Based on Blends of Poly(Butylene Adipate-Co-Terephthalate) (PBAT) and Thermoplastic Starch Filled with Montmorillonite (MMT): Physico-Mechanical Properties.

Poly(butylene adipate-co-terephthalate) (PBAT) is widely used for production of biodegradable films due to its high elongation, excellent flexibility, and good processability properties. An effective way to develop more accessible PBAT-based bioplastics for wide application in packaging is blending of PBAT with thermoplastic starch (TPS) since PBAT is costly with prices approximately double or even triple the prices of traditional plastics like polyethylene. This study is focused on investigating the influence of TPS/PBAT blend ratio and montmorillonite (MMT) content on the physical and mechanical properties and molecular mobility of TPS-MMT/PBAT nanocomposites. Obtained TPS-MMT/PBAT nanocomposites through the melt blending process were characterized using tensile testing, dynamic mechanical thermal analysis (DMTA), and X-ray diffraction (XRD), as well as solid-state 1H and 13C NMR spectroscopy. Mechanical properties demonstrated that the addition of TPS to PBAT leads to a substantial decrease in the tensile strength as well as in the elongation at break, while Young's modulus is rising substantially, while the effect of the MMT addition is almost negligible on the tensile stress of the blends. DMTA results confirmed the formation of TPS domains in the PBAT matrix. With increasing TPS content, mobility of starch-rich regions of TPS domains slightly increases. However, molecular mobility in glycerol-rich regions of TPS domains in the blends was slightly restricted. Moreover, the data obtained from 13C CP/MAS NMR spectra indicated that the presence of TPS in the sample decreases the mobility of the PBAT chains, mainly those located at the TPS/PBAT interfaces.

Improving the compatibility and toughness of sustainable polylactide/poly(butylene adipate-co-terephthalate) blends by incorporation of peroxide and diacrylate

Polylactide/poly(butylene adipate-co-terephthalate) (PLA/PBAT) blends were compatibilized using dicumyl peroxide (DCP) and poly(ethylene glycol) 600 diacrylate (PEG600DA) through a one-step melt-blending process. The compatibility and performance of these blends were subsequently characterized. The results showed that grafts formed “in situ” effectively improved the compatibility and interfacial adhesion between PLA and PBAT phases. Melt viscosity and elasticity of both the PLA/PBAT/DCP and PLA/PBAT/DCP/PEG600DA blends evinced significant increases. Compared to PLA alone, both cold and melt crystallization abilities of the PLA/PBAT/DCP/PEG600DA blends were enhanced, with crystallinities increasing by 5 % - 10 %. Furthermore, the thermal stability, as well as hydrophobicity and oleophobicity of the compatibilized blends improved. In comparison with PLA, the elongation at break and notched impact strength for the PLA/PBAT/DCP/PEG600DA (60/40/0.1/4) blend achieved increases of 290 % and 44.23 kJ/m2, corresponding to improvements of 279 % and 1457 %, respectively. The toughening effect was substantially influenced by the ductile matrix (either a co-continuous phase or a flexible PBAT matrix) in addition to the strong interfacial adhesion and fine phase domain. These eco-friendly blends exhibit considerable potential for packaging articles and 3D printing products owing to their excellent mechanical properties and enhanced melt rheology.

Investigation on mechanical, electrical and morphological of high-density polyethylene (HDPE) reinforced with different particle size and composition of graphene nanoplatelets (GNP)

Graphene nanoplatelets (GNP) are just one of the attractive graphene-based nanomaterials that are rapidly emerging and have sparked the interest of many industries. These small stacks of platelet-shaped graphene sheets have a unique size and morphology that quickly disperse into other materials such as polymers, resulting in higher-value composite materials with improved thermal, conductivity, and mechanical capabilities. A detailed analysis of reinforced High-Density Polyethylene (HDPE) using different sizes (2, 15, 25 µm) and compositions (8, 10, 15 wt.%) of Graphene Nanoplatelets (GNP) has been conducted. The microstructure of the HDPE/GNP nanocomposites was extensively examined during the melt blending and injection moulding processes. Based on the results, the nanocomposites with different sizes of GNP exhibited dissimilar behaviour with different compositions. Furthermore, scanning electron microscope (SEM) results indicated a homogeneous dispersion for GNP in melt mixing. Moreover, thermogravimetric (TG) data demonstrate that increasing filler showed a slight increase in the material's thermal stability. The use of GNP improved mechanical properties, as evidenced by the increases in Young's modulus of yield strength from around 100 MPa to over 400 MPa. This study provides a practical reference for the industrial preparation of polymer-based graphene nanocomposites.

Preparation of ionic liquid modified graphene and its effect on enhancing the properties of PA6 composites

AbstractIn this study, an ionic liquid (IL) with imidazole and amide groups has been prepared, and used to modify graphene (TSG) by ball milling to fabricate ionic liquid functional graphene (TSG‐IL). During the melt blending process, TSG‐IL forms hydrogen bond with the amide group of PA6, which destroys the hydrogen bond of PA6 itself, enhances the interfacial force between TSG‐IL and PA6 matrix, and improves the dispersion of TSG‐IL in PA6 matrix. There has been some improvement in the mechanical and thermal conductivity of PA6 composites. Additionally, the presence of amide groups makes it easy to form hydrogen bonds between TSG‐IL sheets, thus strengthening the connection between TSG‐IL and each other, which is conducive to the construction of thermal conductivity network. The findings indicate that compares to TSG/PA6 composites with the same filler amount, the TSG‐IL/PA6 composites have better heat conductivity and higher mechanical characteristics. 9 wt.% TSG‐IL/PA6 composite has the highest thermal conductivity (0.498 W·m−1·k−1), which is 92.3% and 17.2% greater than that of pure PA6 and 9 wt.% TSG/PA6, and its impact strength (11.12 kJ/m2) is 11.0% and 7% higher, which would be a popular candidate material in the field of thermal conductivity.Highlights Imidazole ionic liquids with amide groups was synthesized. Amide groups were modified onto graphene sheets by ball‐milling. The dispersion of TSG‐IL in PA6 was studied. Improved mechanical property and thermal conductivity of TSG‐IL/PA6 composites.

Electromagnetic interference shielding performance of lanthanum ferrite with MWCNT and graphene in the polyethylene polymer matrix in X-band frequency

In the present study, a combination of Lanthanum ferrite (LaFeO3) magnetic nanoparticles with multi-walled carbon nanotubes (MWCNT) and graphene nanoplatelets (GNP) was prepared and used as conducting filler. As prepared Nanofillers were incorporated with the Low-density polyethylene (LDPE) with the melt blending process. The polymer composite was used to study the electromagnetic interference (EMI) shielding behaviour from 8.2 to 12.4 GHz. The electromagnetic (EM) wave shielding was ascribed to the dielectric and magnetic loss phenomena by incorporating graphene, MWCNT, and LaFeO3. The maximum shielding effectiveness of 33.57 dB was obtained with the critical concentration of 50:5:40:5 wt% sample.

A new method based on TGA/FTIR coupling to quantify the different thermal degradation steps of EVA/HNT composites prepared by different processing

The aim of the present article is to expose a new method based on TGA-FTIR coupling to quantify the different steps of the thermal degradation of EVA in the presence of HNT. Moreover, this quantification of the thermal degradation was also correlated to the color change. EVA/HNT composites were processed with different processing conditions: solvent casting in THF or melt blending at different temperatures. The HNT fillers content (from 10 wt% up to 30 wt%) and the melt blending temperature (at 130 °C, 150 °C, 170 °C and 190 °C) were varied. The thermal degradation of EVA in the presence of HNT presents three noticeable steps as evidenced by TG analysis: i) P1, which was identified as the catalytic degradation of vinyl acetate (VA) part of EVA occurring during the heating ramp (around 250 °C), ii) P2, which is the main degradation of VA (around 350 °C) and iii) P3, which is the degradation of the polyethylene chain of EVA (around 500 °C). Nevertheless, in the case of melt blended EVA/HNT composites, macroscopic changes (strong smell and browning color) indicate a thermal degradation occurring during the melt blending process, namely P0. FTIR-TGA coupling allows to quantify the contribution of P0, P1 and P2 (thermal degradation of VA units of EVA) using Gram Schmidt curves of released acetic acid gas which are obtained from the COac. band of acetic acid at 1795 cm−1. The contribution of each thermal degradation step of the VA part of EVA (named P0 to P2) was then quantified and reported as A0 to A2, respectively. The blending process (solvent or melt) such as the HNT fillers content and the melt blending temperatures have a significant influence on the EVA thermal degradation catalyzed by HNT. For example, it was shown that the thermal degradation of VA units occurring during the processing of EVA+ 30HNT composite (named A0 and catalyzed by the HNT) was of 40% for melt blending process (at 170 °C), whereas it was close to 0% for solvent casting process. Moreover, the macroscopic changes were evaluated by color measurements and an interesting correlation could be made between A0 and ΔE* which is the total color deviation. When a significant catalytic effect, during the melt process was observed (A0 values higher than 5%), the total color deviation ΔE* was increased linearly with A0. Finally, in order to avoid the catalytic effect of HNT on the EVA thermal degradation, a functionalization strategy has been developed with an organosilane leading to the suppression of P1, the catalytic degradation of VA in TG analyses.