Thermoplastic Elastomer Blends Research Articles

Design of interconnected graphene loaded thermoplastic elastomeric blend composite films for minimizing electromagnetic radiation and efficient heat management

AbstractIn this work, electrically conductive thermoplastic elastomeric blend composite films based on polystyrene (PS)/ethylene‐co‐methyl acrylate (EMA) filled with functionalized graphene were developed via the solution mixing technique. Morphological analysis revealed that selective localization of amine‐functionalized reduced graphene oxide (G‐ODA) sheets in the EMA phase of co‐continuous binary blend formed a well‐connected dense conductive pathway by graphene sheets ultimately facilitating the double percolation phenomenon. The electrical percolation threshold was achieved at ~2 wt% of G‐ODA loading which was much lower than that for both single polymer composites. An electrical conductivity of 0.9 S/cm was obtained for blend composite film with 10 wt% of graphene concentration whereas for the same filler loading, PS and EMA composites exhibited electrical conductivity of 1.9 × 10−1 and 2.3 × 10−1 S/cm, respectively. The obtained thermal conductivity of the blend composite with 10 wt% of G‐ODA loading was 0.95 W/m K with 400% enhancement compared to the neat blend system. The same composite exhibited increased real and imaginary permittivity of 92 and 83, respectively. The electrical percolation threshold is well‐correlated with the percolation concentration found from storage modulus and thermal conductivity data. The fabricated PS/EMA blend composite film exhibited absorption‐dominant electromagnetic interference SE of −25 and − 35 dB in X‐band frequency (8.2–12.4 GHz) for 10 wt% of graphene loading with a sample thickness of 0.5 and 1 mm, respectively.

Enhancing electrical characteristics and electromagnetic interference shielding effectiveness in thermoplastic elastomeric polymer blends by utilizing the selective distribution of conductive black

The selective distribution of filler within polymer blends presents a compelling advantage, notably manifesting as a reduced percolation threshold when compared to an individual polymer matrix with a random filler dispersion. In this context, a thermoplastic elastomeric (TPE) blend comprising ethylene propylene diene rubber (EPDM) and linear low-density polyethylene (LLDPE), denoted as EL, has been meticulously formulated. The incorporation of varying amounts of conductive carbon black (Vulcan XC 72; VCB) into this TPE matrix has been achieved through conventional melt blending, yielding a composite material with exceptional electromagnetic interference (EMI) shielding effectiveness of -27.80 dB at 50 phr (parts per hundred rubber). This success is credited to the creation of a linked structure resulting from a dual-step percolation process. The selective distribution of carbon black (CB) throughout the TPE mixture results in a decreased critical concentration for connectivity and enhanced electromagnetic interference (EMI) shielding performance. This advancement underscores the potential of EPDM-LLDPE-VCB (ELV) composites to safeguard against electromagnetic radiation. It paves the way for their utilization in various techno-commercial applications, where a balance of mechanical strength, thermal stability, and flexibility is crucial.Graphical

Phase Morphology and Mechanical Properties of Super-Tough PLLA/TPE/EMA-GMA Ternary Blends.

The inherent brittleness of poly(lactic acid) (PLA) limits its use in a wider range of applications that require plastic deformation at higher stress levels. To overcome this, a series of poly(l-lactic acid) (PLLA)/biodegradable thermoplastic polyester elastomer (TPE) blends and their ternary blends with an ethylene-methyl acrylate-glycidyl methacrylate (EMA-GMA) copolymer as a compatibilizer were prepared via melt blending to improve the poor impact strength and low ductility of PLAs. The thermal behavior, crystallinity, and miscibility of the binary and ternary blends were analyzed by differential scanning calorimetry (DSC). Tensile tests revealed a brittle-ductile transition when the binary PLLA/20TPE blend was compatibilized by 8.6 wt. % EMA-GMA, and the elongation at break increased from 10.9% to 227%. The "super tough" behavior of the PLLA/30TPE/12.9EMA-GMA ternary blend with the incomplete break and notched impact strength of 89.2 kJ∙m-2 was observed at an ambient temperature (23 °C). In addition, unnotched PLLA/40TPE samples showed a tremendous improvement in crack initiation resistance at sub-zero test conditions (-40 °C) with an impact strength of 178.1 kJ∙m-2. Morphological observation by scanning electron microscopy (SEM) indicates that EMA-GMA is preferentially located at the PLLA/TPE interphase, where it is partially incorporated into the matrix and partially encapsulates the TPE. The excellent combination of good interfacial adhesion, debonding cavitation, and subsequent matrix shear yielding worked synergistically with the phase transition from sea-island to co-continuous morphology to form an interesting super-toughening mechanism.

A general strategy to prepare macro-/mesoporous materials from thermoplastic elastomer blends

This work demonstrates a simple method to prepare hierarchically porous materials. The introduction of macropores in mesoporous matrix enables its improved sorbent performance against pollutants for water remediation.

Effect of electron beam radiation on the mechanical, electrical, heat shrinkable and morphological properties of linear low-density polyethylene/polyolefin elastomer blends

The blending of polymers is an efficient means for developing new materials in a less hazardous and more economical way compared to the synthetic route. Polymers with different properties are blended to obtain a new material with combined properties. In this study, a thermoplastic elastomer blend is prepared by melt mixing a metallocene-based polyolefin elastomer (Engage 8003, abbreviated as EN) with linear low-density polyethylene (LLDPE, abbreviated as LL) using a twin-screw extruder in various compositions. To investigate the effect of the electron beam on the properties, LL, EN and their blends are irradiated in the 50–250 kGy dose range. The samples are subjected to gel fraction, mechanical, dynamic mechanical, hardness, heat shrinkability, volume resistivity and morphological studies. The % gel fraction, hardness and heat shrinkability of a sample increase with an increase in the irradiation dose. With increasing LL content, Young’s modulus and ultimate tensile strength of the blends are increased, maintaining the % elongation at break in an attractive region. LE64 (60 wt% LL and 40 wt% EN) and LE46 (40 wt% LL and 60 wt% EN) blends show optimized mechanical and dynamic mechanical properties. Irradiation further increases the tensile strength and Young’s modulus of LE64 up to 150 kGy and LE46 up to 200 kGy. The volume resistivity of the LE64 blend increases tenfold and quadruples for LE46 compared to non-irradiated blends when irradiated at 200 kGy. The morphological structures of the non-irradiated and crosslinked blends support the outcome of the obtained properties nicely.

Effects of Hybrid POSS Nanoparticles on the Properties of Thermoplastic Elastomer-Toughened Polyamide 6.

In this study, polyamide 6 (PA6)/thermoplastic elastomer (TPE) blends were prepared to decrease the notch sensitivity of PA6 for automotive applications, and the morphological, rheological, mechanical, and thermal properties of PA6/TPE blends, which are partially miscible or immiscible depending on the TPE ratio, were significantly improved in the existence of polyhedral oligomeric silsesquioxane (POSS) nanoparticles with multiple reactive epoxy groups as compatibilizers. An unstable phase morphology was obtained with the addition of TPE into PA6 without POSS nanoparticles, whereas interfacial interactions between phases in the presence of POSS were enhanced as a result of a significant decrease in the average particle size from 1.39 to 0.41 μm. The complex viscosity value of the 70PA6/30TPE blend, which was 20 kPa/s-1 at 0.1 rad/s angular frequency, reached 380 kPa/s-1 with the addition of POSS due to the formation of long chains by the generation of graft and/or block copolymers, which resulted in a 65% increase in Young's modulus value. Most notably, the Izod impact strength of pure PA6, which was 10 kJ/m2, increased by 290% with the incorporation of POSS. It was confirmed by FTIR analysis that the reactive multiple epoxy groups of MultEpPOSS and EPPOSS nanoparticles react with the proper groups of PA6 and/or TPE, and also, a partial hydrogen bonding interaction occurs between PA6-TPE from the shifting of N-H and carbonyl peaks. In conclusion, it can be suggested that POSS nanoparticles can serve as highly effective compatibilizers for PA6/TPE blends and have potential commercial applications, especially in the automotive sector.

Shape Memory Behavior and Self-Healing Effects of Dynamically Vulcanized TPU/ENR Thermoplastic Elastomeric Blends

Shape Memory Behavior and Self-Healing Effects of Dynamically Vulcanized TPU/ENR Thermoplastic Elastomeric Blends

Self‐healing thermoplastic elastomeric blends of zinc‐ionomer and styrene–butadiene–styrene block copolymer and their characterization

AbstractWe report the development of novel self‐healing binary thermoplastic elastomeric blends of Zn2+‐neutralized poly[ethylene‐co‐(methacrylic acid)] (Zn‐ionomer) and styrene–butadiene–styrene block copolymer (SBS). Zn‐ionomer/SBS blends were prepared by the melt‐blending technique using a twin‐screw extruder with three mass ratios of 75/25, 50/50 and 25/75. Structure, phase morphology and thermal as well as tensile properties of the samples were characterized. Fourier transform infrared spectroscopy results indicated the presence of two types of polymeric materials and their interactions. Scanning electron microscopy images confirmed the miscibility of blend components which remarkably influenced the properties of the blends. The optimum peak degradation temperature of Zn‐ionomer/SBS (75/25 wt%) blend was observed to be 484 °C. The ratio of the tensile strength of the healed specimens to that of the original specimens was implemented to quantitatively evaluate the self‐healing efficiency of the materials. The self‐healing efficiencies were calculated to be 55.42%, 58.36% and 60.75% for Zn‐ionomer samples healed for 4, 8 and 16 h, respectively. All of the blend samples exhibited self‐healing behavior and the self‐healing efficiency was more than that of virgin Zn‐ionomer which may be credited to the high mobility of SBS segments in the blends. The healing efficiency was increased with an increase of SBS content in the blends and also heat energy facilitated the healing process. The self‐healing efficiencies of Zn‐ionomer/SBS (25/75 wt%) blend sample were calculated to be 75.09%, 80.27% and 80.87%, respectively, for 4, 8 and 16 h of healing time at 100 °C. A comparison of optical micrographs of the cut area of samples (before healing and after the healing process) was also made and self‐healing of the blend materials was observed. © 2023 Society of Industrial Chemistry.

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

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

Lightweight Antistatic Thermoplastic Elastomer Blend Foam: The Foaming Behavior and Mechanical Properties

A thermoplastic polyester elastomer (TPEE) has been widely used because of its excellent impact resistance and resilience, but its melt viscosity is too low to be used in the supercritical foaming. In addition, TPEE easily generates static electricity accumulation during processing, which has a risk of fire. Herein, a thermoplastic polyamide elastomer (PEBAX) with permanent antistatic properties was blended with TPEE, and triglycidyl isocyanurate (TGIC) was used as a chain extender to improve the compatibility and melt strength of the blends. Then, the TPEE/PEBAX blends were foamed by supercritical N2, and the cell structure and mechanical and antistatic properties of the blend foam were analyzed at a density of 0.1 ± 0.001 g/cm3. The results showed that when the blending ratio of TPEE/PEBAX was 70/30, the blend foam with a uniform cell structure had the most excellent mechanical properties. The resilience and elongation at break reached 83 and 850.3%, respectively. In addition, the surface resistivity and volume resistivity were 3.21 × 109 Ω and 7.35 × 109 Ω·cm, respectively, which were significantly lower than those of the IEC 61340 standard.

Combination effect of functionalized high aspect ratio carbonaceous nanofillers and carbon black on electrical, thermal conductivity, dielectric and EMI shielding behavior of co-continuous thermoplastic elastomeric blend composite films

The utilization of conductive hybrid carbonaceous fillers to fabricate highly efficient electromagnetic interference (EMI) shielding materials has become a popular area of research interest recently. Here, we report the facile fabrication of lightweight thermoplastic elastomeric blend composite films by solution mixing technique, taking advantage of both the hybrid carbonic nanofillers (high aspect ratio carbon inclusion and conductive carbon black) and the co-continuous polystyrene (PS)/ethylene-co-methyl acrylate (EMA) blend. Combination of acid-functionalized multiwalled carbon nanotubes (f-CNT) and carbon nanofibers (f-CNF) with conductive Vulcan-XC 72 carbon black (VCB) aids in the more uniform dispersion of hybrid carbonaceous inclusion in this blend system. The selective location of hybrid nanofillers in EMA phase of binary polymer mix enhanced the electrical properties, thermal conductivity, and microwave shielding performance of the resultant blend composites by constructing a dense, co-supportive, double percolated conductive network throughout the blend. The effect of f-CNT or f-CNF concentration in hybrid composites on the above-mentioned properties of blend composites has been investigated in this work. The as-prepared PS/EMA/VCB/f-CNT and PS/EMA/VCB/f-CNF blend composite films exhibited a thermal conductivity of 0.81 and 0.83 W/m.K and absorption-dominated microwave shielding of -31 and -32.5 dB, respectively with 15 wt% hybrid filler loading containing 50 wt% of f-CNT or f-CNF. These conductive thermal management composite films could be excellent choices to mitigate EM pollution.

High vinyl polybutadiene rubber/polypropylene thermoplastic elastomer blends: Optimization of internal mixing process parameters and screening of processing methods

AbstractThermoplastic vulcanizates (TPV) composed of high vinyl polybutadiene rubber (HVPB) and polypropylene (PP) have good thermal stability and damping properties. This work aims to apply a design of experiments (Taguchi L9 orthogonal array) to optimize the mixing parameters (rotor speed, temperature, and time) for the HVPB/PP TPV. The effects of these mixing parameters on its physical and mechanical properties of HVPB/PP TPV follow the order: rotor speed > temperature and time. In the case of the master batch process, the optimum mixing parameters are 60 rpm, 180°C and 8 min. Subsequently, four processes (master batch, static vulcanization, rubber‐plastic premixing, and two‐step processing) are compared using the same optimum mixing parameters. The master batch process turns out to be the best in terms of physical and mechanical properties.

Effect of Molecular Weight on the Morphology of a Polymer Semiconductor–Thermoplastic Elastomer Blend

AbstractPolymer semiconductors (PSCs) are essential active materials in mechanically stretchable electronic devices. However, many exhibit low fracture strain due to their rigid chain conformation and the presence of large crystalline domains. Here, a PSC/elastomer blend, poly[((2,6‐bis(thiophen‐2‐yl)‐3,7‐bis(9‐octylnonadecyl)thieno[3,2‐b]thieno[2′,3′:4,5]thieno[2,3‐d]thiophene)‐5,5′‐diyl)(2,5‐bis(8‐octyloctadecyl)‐3,6‐di(thiophen‐2‐yl)pyrrolo[3,4‐c]pyrrole‐1,4‐dione)‐5,5′‐diyl]] (P2TDPP2TFT4) and polystyrene‐block‐poly(ethylene‐ran‐butylene)‐block‐polystyrene (SEBS) are systematically investigated. Specifically, the effects of molecular weight of both SEBS and P2TDPP2TFT4 on the resulting blend morphology, mechanical, and electrical properties are explored. In addition to commonly used techniques, atomic force microscopy‐based nanomechanical images are used to provide additional insights into the blend film morphology. Opposing trends in SEBS‐induced aggregation are observed for the different P2TDPP2TFT4 molecular weights upon increasing the SEBS molecular weight from 87 to 276 kDa. Furthermore, these trends are seen in device performance trends for both molecular weights of P2TDPP2TFT4. SEBS molecular weight also has a substantial influence on the mesoscale phase separation. Strain at fracture increases dramatically upon blending, reaching a maximum value of 640% ± 20% in the blended films measured with film‐on‐water method. These results highlight the importance of molecular weight for electronic devices. In addition, this study provides valuable insights into appropriate polymer selections for stretchable semiconducting thin films that simultaneously possess excellent mechanical and electrical properties.

Improving the ductility, toughness, and electrical conductivity of poly(lactic acid) by forming poly(lactic acid)/thermoplastic polyester elastomer blend and blend‐based nanocomposites

AbstractIn this study, poly(lactic acid) (PLA)/thermoplastic polyester elastomer (TPEE) (70/30) blend and blend‐based nanocomposites with carbon nanotube (CNT) as a nanofiller were fabricated by conventional melt mixing. Scanning electron microscopy results showed that the blend had a biphasic morphology, and CNTs were selectively distributed in the dispersed TPEE domains in the composites. The presence of CNTs induced the agglomeration and shape modification of TPEE domains, consequently influencing the examined properties. Differential scanning calorimetry results revealed that the crystallizability of PLA was improved after blending with TPEE, and further CNT incorporation increased the crystallization temperature of TPEE during cooling. The elongation at break (EB) and notched impact strength (IS) of PLA were evidently improved in the blend and composites. In particular, the EB and IS in the composites increased by up to 290% and 43%, respectively. The electrical resistivity of neat components and the blend decreased by up to eight orders of magnitude after 3 phr CNT loading due to double percolation in TPEE domains and dispersed CNTs. A percolation threshold at ca. 1 phr CNT loading for electrical conductivity was determined. Rheological property analysis suggested the formation of a pseudo‐network structure, which was attributed to the CNTs increasing the viscosity of the TPEE domains in the composites.

Construction of stimuli-responsive and mechanically-adaptive thermoplastic elastomeric materials

The stimuli-responsive systems present in nature have inspired scientists to develop new-generation synthetic mechano-adaptive materials for various technological applications. In this work, an effective strategy was adopted to construct a biomimetic mechano-adaptive thermoplastic elastomeric material, whose mechanical properties can be stimulated by water. The inherent ability of calcium sulphate (CaSO4) to reversibly alter its crystal structure by the hydration/dehydration process was exploited in a technologically compatible hydrophilic thermoplastic elastomeric (TPE) blend by dispersing it as a phase responsive filler. Significant enhancements in the mechanical properties were then achieved in the water-treated CaSO4 filled TPE composite. The improved mechanical properties of the water-treated composite originated with the creation of in-situ hydrated nanosized CaSO4 crystals were also correlated with the strong filler-filler interactions and higher aspect ratio of the filler. The storage modulus (dynamic stiffness) of the resulting TPE composite could be reversibly altered from ∼9.6 to ∼46.7 MPa. Most importantly, ∼92% mechanical adaptivity of the resulting TPE composite was achieved due to the reversible transformation of nanosized crystals into a hemihydrate mesocrystalline form by exploiting the hydration/dehydration process. The alteration of in-situ polymorphic CaSO4 phase morphological structures was verified using transmission electron microscopy, Raman spectroscopy and X-ray diffraction. This technique provides a unique pathway for the creation of next-generation stimuli-responsive TPE materials by controlling the polymorphic phase morphological structure of mineral filler.

Carbon nanotubes and carbon nanofibers based co-continuous thermoplastic elastomeric blend composites for efficient microwave shielding and thermal management

Microwave absorbing materials based on polymer blend composites are now receiving great interest to mitigate radiation pollution at ultra-low filler concentrations. Herein, polystyrene (PS)/ethylene-co-methyl acrylate (EMA) thermoplastic elastomeric blend composites were prepared via wet mixing utilizing acid-functionalized multi-walled carbon nanotubes (MWCNTs) and carbon nanofibers (CNFs). The development of a compact spatial conductive network throughout the matrix as a result of selective confinement of these functionalized nanofillers in EMA phase of the PS/EMA co-continuous blend reduces the electrical percolation threshold significantly. Higher aspect ratio of FCNFs helps to construct more interconnected conductive pathway in the composite than FCNTs. The thermal conductivity obtained for PS/EMA/FCNT and PS/EMA/FCNF blend composites with 15 wt% of filler concentration are 0.84, 0.86 W/m.K, respectively. The as-preparedcomposites have an absorption-dominant EMI shielding performance of −36.7 dB for 15 wt% of nanofiber loading. These highly efficient EMI shields may be applied in the future generation wearable electronics.

Study of Compatibility and Flame Retardancy of TPU/PLA Composites.

In order to apply the rigid biodegradable PLA material for flexible toothbrush bristle products, in this paper, Poly(lactic acid) (PLA) and thermoplastic polyurethane elastomer (TPU) blends (TPU/PLA composites), with a mass ratio of 80:20, were prepared by the melt-blending method to achieve toughening modification. Infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry and low-field nuclear magnetic resonance were used to investigate the effect of the compatibilizer, Maleic anhydride grafted polypropylene (PP-g-MAH), on the compatibility of the blends, and the effect of melamine on the flame retardant properties of the blends was further investigated. The results demonstrated that 3% PP-g-MAH had the best compatibility effect on PLA and TPU; the TPU/PLA composites have a better macromolecular motility and higher crystallization capacity in the amorphous regions through the physical and chemical action by using PP-g-MAH as a compatibilizer. By adding melamine as a flame retardant, the scorch wire ignition temperature of TPU/PLA composites can reach 830 °C, which was elevated by 80 °C compared with pure PLA; however, the flame retardant effect of melamine in a single system was not significant. Melamine acts as a flame retardant by absorbing heat through decomposition and diluting the combustible material by producing an inert gas.

Development of high melt strength polypropylene and its application in thermoplastic elastomeric composition

High melt strength polypropylene (HMS-PP) with a long-chain branched structure is a modified form of polypropylene (PP) which has basic properties of regular PP but with superior melt drawability. This paper reports on the development of gel-free HMS-PP from a linear isotactic PP through the introduction of long-chain branching on its backbone via a reactive extrusion process, using dicetyl-peroxydicarbonate (PODIC) alone or in combination with a coagent. The melt strength and the mechanical properties such as impact and flexural strength of PP showed improvements with the modification with PODIC. 5000 ppm by weight of PODIC was found to provide the best balance of properties. The efficacies of zinc diethyldithiocarbamate (ZDC) and tetramethyl thiuram disulphide (TMTD) as coagents in combination with PODIC to augment properties of HMS-PP further were explored. TMTD offered slightly enhanced performance benefits as compared to ZDC at an optimized concentration of 100 ppm by weight. The application potential of HMS-PP in thermoplastic elastomeric blends of HMS-PP with ethylene-propylene-diene monomer (EPDM) rubber at a fixed ratio of 35/65 by weight was also investigated. Structure-property correlations were established between the extent of long-chain branching in the modified PP and the properties of the resultant thermoplastic elastomeric composition.

Thermo-responsive and electro-active shape memory poly(styrene-b-isoprene-b-styrene)/poly(ethylene-co-1-octene)/graphene composites: Effect of size of graphene nanoplatelets

Thermally and electrically triggered poly(styrene-b-isoprene-b-styrene) (SIS) and poly(ethylene-co-1-octene) (PEO) thermoplastic elastomer blend composites having a SIS/PEO weight ratio of 40/60 were prepared by melt blending method. Two different graphene nanoplatelets (GnPs) with different sizes (small size (SG) and big size (BG)) were used as conductive fillers at different amounts. The thermo-responsive and electro-active shape memory performances of the composites as well as their morphological, mechanical and thermal properties were investigated by paying attention to the effect of size and loading degree of the graphene nano-fillers. Both the BG and the SG improved elastic modulus with increase in amount of the fillers. The modulus values increased by 553 % and 507 % for the 50BG and 50SG composites having 50 phr GnPs respectively, as compared to the blend. Heat-triggered thermo-mechanical shape memory tests showed that the BG filler is more advantageous for shape fixing whereas the SG filler is favorable to shape recovery ability. The electrical percolation threshold was achieved at relatively lower content for the BG filler. The 50BG composite exhibited electro-active shape recovery under 25 V, while the SG composite recovered its shape under 65 V. The thermal stability of the blend significantly improved by the use of the both fillers. The degradation onset temperatures of the 50SG and the 50BG composites increased by 25 °C and 10 °C, respectively, compared to the blend.

A review on graft compatibilizer for thermoplastic elastomer blend

A biodegradable thermoplastic elastomer (TPE) blend is developed by blending poly (lactic acid) (PLA) and natural rubber (NR) or epoxidized natural rubber (ENR) and it is a sustainable substitution in recent years for synthetic polymers. PLA is high in mechanical strength and compostable, but it is highly stiff and brittle. The incorporation of NR or ENR to PLA increases the impact strength and toughness of PLA. However, the disparity in polarity between PLA and elastomer phase like NR and ENR results in TPE blend being incompatible. Hence, compatibilization is essential to improve its polarity and develop interactions. Compatibilizer that composed of two different polymer is known is graft compatibilizer with the aid of grafting agent. The graft compatibilizers are divided into two categories. The first type is made up of one polymer and grafting agent and, the other one is composed of two polymer groups and grafting agent. These two types of graft compatibilizer can be prepared via two different method such as direct melt blending and solution. Apart from this, the TPE blend is produced via the melt blending technique with mixing machines such as internal mixer and extruder. This article has reviewed the preparation of the graft compatibilizer and blending technique of TPE. Based on the findings, the graft compatibilizers has a significant role in improving miscibility and compatibility across blend composed of different phase.