Effect Of Compatibilizer Research Articles

Effect of Maleic Anhydride Grafted Ethylene Vinyl Acetate Compatibilizer on the Mechanical, Thermal Properties and Weathering Resistance of Polyamide 11/Bamboo Fiber Composite

In this research, short bamboo fiber (BF) has been used as filler in the fabrication of the composite based on polyamide 11 (PA11) by melt-mixing method. In order to improve the compatibility between BF and PA11, maleic anhydride grafted ethylene vinyl acetate copolymer (EVAgMA) was introduced into the composite preparation process. The effect of EVAgMA contents on mechanical, thermal or weathering resistant properties of the composites was investigated. In the presence of the EVAgMA, the tensile strength, impact strength and flexural modulus of composites showed the improvement in comparison to without compatibilizer. Differential scanning calorimetry (DSC) analysis indicated that the melting temperature of composites did not depend on the EVAgMA contents, while its fusion heat (ΔHm) decreased with increasing EVAgMA contents. Dynamic mechanical thermal analysis (DMTA) evaluated the role of EVAgMA on the enhancement of composites’s storage modulus (G′) in the glassy plateau and the interaction between BF and PA11 matrix. After 840 hours of accelerated weathering test, the composites using EVAgMA were decomposed faster than that of neat PA11 and PA11/BF composite. This result was also agreed with the observation of scanning electronic microscopy (SEM) images and the change of carbonyl index (CI). However, the retention of tensile properties of PA11/EVAgMA/BF composites is higher than that of PA11/BF composite.

Effect of Poly(phenylene sulfide) (PPS) as Functional Additive on the Physical Properties of Poly(phenylene ether) (PPE)/PPS Blends

Abstract In this study, polyphenylene sulfide (PPS) was introduced in polyphenylene ether (PPE) blend to improve the processability of PPE and to secure the flame retardancy of the blend without deteriorating physical properties. Through the study of the binary blend of PPE/PPS, it was found that the shear thinning behavior and the external lubrication effect of PPS can improve the processability of PPE. Thermal analysis of the blend showed that the glass transition temperature of the PPS component decreases by the plasticization while that of the PPE component increases by the anti-plasticization effect. The modulus of the binary blend increased with the PPS content, and the tensile strength decreased but followed the additive rule. The change in tensile properties can be explained by the synergy effect of partial miscibility between PPE and PPS due to structural similarity, and non-isotropic morphology formation. Impact strength increased sharply in PPE60 due to the mechanical grafting effect by co-continuous phase formation. In the ternary blend with SEBS-MAH applied to PPE60, the impact strength steep increased at a content of 10 wt% or more due to the dramatic morphology change based on the compatibilization effect. Flame retardancy of V0 was also observed in all compositions where SEBS-MAH was applied within 20 phr.

Effect of Olefin-based Compatibilizers on the Formation of Cocontinuous Structure in Immiscible HDPE/iPP Blends

In this work, the formation of cocontinuous structure in immiscible high density polyethylene/isotactic polypropylene (HDPE/iPP) blends was investigated for various olefin-based compatibilizers of distinct molecular architectures, including ternary random copolymer EPDM, olefin block copolymer (OBC), polypropylene-based OBC (PP-OBC), ethylene/a-olefin copolymer (POE), bottlebrush polymer poly(1-dodecene), and comb-like poly(propylene-co-high a-olefin) (PPO). The scanning electron microscopy results show that after adding OBC, PP-OBC, and POE copolymers, the finer droplet-in-matrix morphologies were obtained in 70/30 HDPE/iPP blend. Interestingly, for 70/30 HDPE/iPP blend with just 5 wt% of PPO copolymers, the phase inversion from droplet-in-matrix to cocontinuous morphology can be observed. It was proposed that the development of cocontinuous morphology contained the following steps: (1) interfacial saturation of compatibilizers and droplet deformation, (2) droplet-droplet coalescence, (3) continuity development, and (4) the formation of dual-phase continuity. Among the diverse copolymers studied in this work, PPO copolymer can be easily removed out of the interface during droplet coalescence and stabilize the curvature of minor fiber phase, facilitating the formation of cocontinuous morphology. In contrast, other olefin-based compatibilizers (EPDM, OBC, PP-OBC, and POE) exhibit the distinct steric repulsion effect to prohibit droplet coalescence. Moreover, the cocontinous interval varies with the compatibilizer architectures. Surprisingly, after adding 10 wt% of PPO copolymers, the cocontinuous interval was greatly broadened from HDPE/iPP range of 45/55–60/40 to that of 40/60–70/30.

SEBS-b-TPU and nanoclay: effective compatibilizers for promotion of the interfacial adhesion and properties of immiscible SEBS/TPU blends

High-performance polystyrene-b-poly (ethylene-butylene)-b-polystyrene/thermoplastic polyurethane (SEBS/TPU) blends containing polyurethane blocked styrene–ethylene–butylene–styrene (SEBS-b-TPU) and SEBS-b-TPU/clay were obtained by melt mixing. The influence of SEBS-b-TPU and nanoclay content on morphology, mechanical, thermal, rheological and abrasion behavior of the SEBS/TPU blends were investigated. SEM results indicated that the domain size of the TPU phase was remarkably reduced by the presence of SEBS-b-TPU. Moreover, the addition of clay further improved the extent of mixing. TEM and SEM–EDX revealed that nanoclays were preferentially located in and along the outer edge of the TPU phase with an intercalated/exfoliated structure. TGA results showed that the degradation temperatures (T5%) were increased by 12.3 °C and 20.8 °C for SEBS/TPU/SEBS-b-TPU-7% and SEBS/TPU/SEBS-b-TPU/clay-3% nanocomposites, respectively, compared with that of SEBS/TPU. There was also an improvement in mechanical and rheological properties as expected. Meanwhile, the abrasion resistance of SEBS/TPU blends was considerably enhanced by the presence of SEBS-b-TPU/clay, the DIN volume loss decreased by as much as 56%, which can be attributed to the dispersion of the clay platelets in nanoscales as well as the enhanced interfacial adhesion. These superior properties of the SEBS/TPU blends are important for many applications.

Influence of graphene oxide on the morphological and mechanical behaviour of compatibilized low density polyethylene nanocomposites

Abstract The research work aims to analyze the effect of graphene oxide (GO) distribution on the morphological, physical, static and dynamic mechanical properties of polyolefin matrices. Polar polymer namely maleic anhydride grafted polyethylene (MA-g-PE) is used as a compatilizer to incorporate GO into low density polyethylene (LDPE). Preparation of polyolefin nanocomposite is carried out by melt-mixing technique. According to ASTM standard, the specimens are prepared through compression molding technique. Mechanical properties of pure and graphene oxide filled polymers are analyzed through universal testing machine. Storage modulus and tan delta characteristics are analyzed through dynamic mechanical analyzer. A series of characterization methods like the X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and transmission electron microscopic (TEM) were performed on the prepared nanocomposites. The effects of compatibilizer and grapheme oxide on polyolefin nanocomposites were investigated by dynamic mechanical analysis (DMA), tensile test and percentage elongation. The XRD results showed increase in intergallery spacing of nanosheets proving the formation of GO from flake graphite. TEM images prove the improved distribution of GO sheets into the polymer matrix in presence of compatibilizer. Compatiblized nanocomposites show significant enhancement in Tensile strength, modulus of elasticity, storage modulus and subsequent decrease in tan delta peak implying minimum heat buildup compared to control. Polar-polar interaction between GO and compatibilizer leads to improved distribution of the nanofiller in the base polymer matrices. This indeed enhances the technical properties of the polymer.

An approach for compatibilization of the starch with poly(lactic acid) and ethylene-vinyl acetate-glycidyl-methacrylate

In this study, we evaluated the possibility of dimethyldidodecylammonium bromide (DDAB)-modified graphene oxide quantum dots (DDAB-GOQDs) as a new compatibilizer to improve the compatibility of hydrophilic starch with hydrophobic polylactic acid (PLA) and ethylene-vinyl acetate-glycidylmethacrylate (EVA-GMA). The successful synthesis of DDAB-GOQDs was verified by Fourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM) and Zeta-Plus assay. The differential scanning calorimetry (DSC), polarized light optical microscopy (POM) and iso-thermal crystallization kinetics analysis showed that 0.25% DDAB-GOQDs could significantly increase the crystallization rate and nucleation density as well as reduce the spherulites size of the nanocomposites. Compared to pure composites, the nanocomposites containing 0.25% DDAB-GOQDs showed obvious enhancement in thermal stability and surface hydrophobicity, with an increase of ~22 °C and ~24.1° in the maximum decomposition temperature and contact angle, coupled with similar improvement in the storage modulus and UV-shielding capacity. Morphological analysis, FTIR and creep behavior experiments revealed that adding 0.25% DDAB-GOQDs enhanced the interface compatibility of the nanocomposites by promoting the formation of the interpenetrated network through strong polar hydrogen bond or electrostatic force within the polymeric components. Overall, (0.25%) DDAB-GOQDs can serve as an effective compatibilizer for the PLA/starch/EVA-GMA system due to improved crystallization, thermal stability, barrier properties and creep-resistance.

Annealing effect on tensile property and hydrolytic degradation of biodegradable poly(lactic acid) reactive blend with poly(trimethylene terephthalate) by two-step blending procedure

A blending procedure utilizing a crystallized, tough, biodegradable poly(lactic acid) (PLA) blend with poly(trimethylene terephthalate) (PTT) and reactive compatibilizer, poly(ethylene-co-glycidyl methacrylate) (PEGMA), produced by two-step blending, was investigated in this research. The effects of the reactive compatibilizer and annealing temperature were investigated using an annealing PLA/PTT/PEGMA blend. The tensile properties of the annealed PLA/PTT/PEGMA blend were drastically improved compared with the annealed neat PLA and PLA/PTT blends. Craze formation was observed in the elongated area of the annealed PLA/PTT/PEGMA blend, and it was suggested to contribute to the toughening of the blend. The crystal's lack of spherulitic morphologies also contributed to the improved tensile properties, as confirmed by polarized optical microscopy (POM) and small-angle light scattering (SALS). The crystallization kinetics of the blends during annealing were also studied. Moreover, hydrolytic degradation of the blend could be controlled, after blending with PTT and PEGMA.

Guar gum (GG) / Methylcellulose (MC) Blends and their Composites with Maghemite Nanoparticles

Miscibility of polymers decides the applicability of the resulting blends and immiscible polymer blends can be made compatible with suitable compatibilizer. Miscibility of blends of guar gum (GG) and methyl cellulose (MC) in common solvent water were studied by refractive index, density, ultrasonic velocity, and dilute solution viscometry methods at 30°C and 40°C. Based on these measurements, it is found that the polymer blend of GG/MC is immiscible. The effect of compatibilization with 0.02 wt% maghemite nanoparticle was studied in aqueous solution and found that 10/90 GG/MC blend is miscible in the presence of maghemite. Solution cast technique was used to prepare thin films of GG/MC blend – maghemite composite and characterized by scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) method.

Development and Characterization of Sustainable Composites from Bacterial Polyester Poly(3-Hydroxybutyrate-co-3-hydroxyhexanoate) and Almond Shell Flour by Reactive Extrusion with Oligomers of Lactic Acid.

Eco-efficient Wood Plastic Composites (WPCs) have been obtained using poly(hydroxybutyrate-co-hexanoate) (PHBH) as the polymer matrix, and almond shell flour (ASF), a by-product from the agro-food industry, as filler/reinforcement. These WPCs were prepared with different amounts of lignocellulosic fillers (wt %), namely 10, 20 and 30. The mechanical characterization of these WPCs showed an important increase in their stiffness with increasing the wt % ASF content. In addition, lower tensile strength and impact strength were obtained. The field emission scanning electron microscopy (FESEM) study revealed the lack of continuity and poor adhesion among the PHBH-ASF interface. Even with the only addition of 10 wt % ASF, these green composites become highly brittle. Nevertheless, for real applications, the WPC with 30 wt % ASF is the most attracting material since it contributes to lowering the overall cost of the WPC and can be manufactured by injection moulding, but its properties are really compromised due to the lack of compatibility between the hydrophobic PHBH matrix and the hydrophilic lignocellulosic filler. To minimize this phenomenon, 10 and 20 phr (weight parts of OLA-Oligomeric Lactic Acid per one hundred weight parts of PHBH) were added to PHBH/ASF (30 wt % ASF) composites. Differential scanning calorimetry (DSC) suggested poor plasticization effect of OLA on PHBH-ASF composites. Nevertheless, the most important property OLA can provide to PHBH/ASF composites is somewhat compatibilization since some mechanical ductile properties are improved with OLA addition. The study by thermomechanical analysis (TMA), confirmed the increase of the coefficient of linear thermal expansion (CLTE) with increasing OLA content. The dynamic mechanical characterization (DTMA), revealed higher storage modulus, E’, with increasing ASF. Moreover, DTMA results confirmed poor plasticization of OLA on PHBH-ASF (30 wt % ASF) composites, but interesting compatibilization effects.

Effect of Different Compatibilizers on the Properties of Poly (Lactic Acid)/Poly (Butylene Adipate-Co-Terephthalate) Blends Prepared under Intense Shear Flow Field

In this report, poly(lactic acid) (PLA) and Poly(butylene adipate-co-terephthalate) (PBAT) with three kinds of compatibilizers were melt blended under intensive shear flow. A self-made parallel three-screw extruder was developed to generate such flow during the process. Mechanical properties, chemical reactions among PLA, PBAT and compatibilizers, rheological behavior and morphology were investigated. The mechanical tests showed that the notched impact strength of super-tough composite with 10 wt% EGMA is about 20 times than that of pure PLA. The Fourier transform infrared spectroscopy (FT-IR) results showed that the epoxy functional groups or maleic anhydride functional groups of KT-20, KT-915 and EGMA reacted with the hydroxyl groups of PLA or PBAT macromolecules, resulting in a bridge of PLA and PBAT. About rheological properties, the tan δ—angular frequency curves and the η’’- η’ curves confirmed the chemical reactions mentioned above and indicated better compatibility of η’’- η’ between PLA and PBAT, respectively. Meanwhile, the loss modulus and storage modulus—angular frequency curves demonstrated the discrepancy of different compatibilizer components. In particular, from scanning electron microscopy (SEM) images, it can be seen that the phase size and dispersion uniformity of PBAT adjusted by compatibilizer, corresponding to better compatibility that is described in the η’’- η’ curves. The approach for producing super-tough PLA/PBAT/compatibilizer by intensive shear flow provides a viable direction for further improving PLA performance.

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Compatibilization Effect of Ionic Liquid-Based Surfactants on Physicochemical Properties of PBS/Rice Starch Blends: An Initial Study.

Polybutylene succinate (PBS)/rice starch (RS) blends were prepared via the hot-melt extrusion technique through the usage of a twin-screw extruder without and containing ionic liquid-based surfactants (ILbS). Two types of ILbS were used, specifically, 1-dodecyl-3-methylimidazolium trifluoromethanesulfonate, [C12mim][OTf] and 1-dodecyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C12mim][NTf2] were mixed into the PBS/RS blends at the different contents (0–8 wt.%). The tensile and flexural results showed that the blends containing ILbS have a high tensile extension and tensile energy compared to the blend without ILbS. The blends containing ILbS also have a high flexural extension compared with the blend without ILbS. The blends containing [C12mim][NTf2] have a significant improvement in the tensile energy (up to 239%) and flexural extension (up to 17%) in comparison with the blends containing [C12mim][OTf]. The FTIR spectra demonstrated that the presence of ILbS in the blends generated the intermolecular interactions (ion-dipole force and hydrophobic-hydrophobic interaction) between PBS and RS. The DSC results exhibited that the melting points of the prepared blends are decreased with the addition of ILbS. However, the TGA results showed that the thermal decomposition of the blends containing ILbS are higher than the blend without ILbS. The values of decomposition temperature were 387.4 °C, 381.8 °C, and 378.6 °C of PBS/RS-[C12mim][NTf2], PBS/RS-[C12mim][OTf], and PBS/RS, respectively. In conclusion, the ILbS could significantly improve the physicochemical properties of the PBS/RS blends by acting as a compatibilizer.

Enhancement of interfacial adhesion in immiscible polymer blend by using a graft copolymer synthesized from propargyl-terminated poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) is a biomass-derived polymer synthesized by the fermentation inside the bacteria, which has excellent flexibility and mechanical toughness. However, the industrial applications of PHBH have been limited because of its poor modulus of elasticity and tensile strength. For improving the mechanical characteristics of PHBH to eventually broaden its industrial applications, it was blended with poly(methyl methacrylate) (PMMA), a rigid polymer. Moreover, blending PHBH was also expected to increase the toughness of PMMA. Nevertheless, PHBH/PMMA blends lack interfacial adhesion due to low miscibility, thus restricting potential applications. This work focusses on enhancing the compatibility of PHBH/PMMA blend by developing a compatibilizer. The synthesis of PMMA-g-PHBH, a graft copolymer, was carried out using methyl methacrylate and vinyl-terminated PHBH derived from propargyl-terminated PHBH. The findings obtained from scanning electron microscopy and thermal analysis showed improvement in the miscibility of PHBH and PMMA upon the inclusion of PMMA-g-PHBH in the blend structure. The mechanical properties of the blends can also be tuned by controlling the weight fraction of PHBH/PMMA/PMMA-g-PHBH. This study proves that PMMA-g-PHBH acts as an effective compatibilizer for PHBH/PMMA blends.

Morphology and Properties of Poly(Lactic Acid)/Ethylene-Octene Copolymer Blends with Different Organoclay Types

This work studied the morphology, mechanical and thermal properties of poly (lactic acid) (PLA)/ethylene-octene copolymer (EOC) (80/20) blends with different organoclay types. Herein, EOC was introduced to toughening PLA by melt blending and organoclay was used to improve compatibility and tensile properties of the blends. The two organoclay types were nanoclay surface modified with aminopropyltriethoxysilane 0.5-5 wt% and octadecylamine 15-35% (Clay-ASO) and nanoclay surface modified with dimethyl dialkyl (C14-C18) amine 35-45 wt% (Clay-DDA). The organoclay contents were 3, 5 and 7 phr. Scanning electron microscope (SEM) observation results revealed PLA/EOC blends demonstrated a two-phase separation of dispersed EOC phase and PLA matrix phase. The addition of organoclay significantly improved the compatibility between PLA and EOC phases due to EOC droplet size decreased dominantly in PLA matrix, so organoclay could act as an effective compatibilizer. The incorporation of organoclay increased significantly tensile strength of PLA/EOC/organoclay composites while Young’s modulus increased with 5 phr of organoclay. The thermal stability of PLA/EOC blends did not change when compared with neat PLA, and when added Clay-ASO in the blends could improve the thermal stability of the PLA/EOC blends.

Morphology and Mechanical Properties of Polyamide 6 and Polybutylene Terephthalate Blends Compatibilized with Epoxidized Natural Rubber

Blends of polyamide 6 (PA6) and, polybutylene terephthalate (PBT) have been prepared in this work. They were compatibilized using epoxidized natural rubber (ENR-50) by varying amount of ENR-50 i.e., 0, 3 and 5 phr. The effect of blend compositions and compatibilization on the phase morphology and properties of the resulting blends were investigated using a scanning electron microscope, universal testing machine, impact testing machine, and hardness shore durometer. All blends were prepared and shaped by using twin-screw extruder at 260°C and injection molding machine, respectively. The results revealed that the phase morphology of the PA6/PBT blend was incompatible. The separation of PA6 and PBT was observed wherein PBT is dispersed in the form of spherical domains in the PA6 matrix. The mechanical properties exhibit loss in tensile and impact strength. This could be attributed to poor interfacial adhesion between the two polymers. SEM micrographs showed that the addition of ENR-50 improved the compatibility of PA6/PBT blends. With the addition of ENR-50 as a compatibilizer, the uniformity and the maximum reduction of dispersed phase sized were achieved. The water absorption of PA6/PBT blends decreased with an increasing amount of PBT. Additionally, the results indicated that, as the amount of ENR-50 increased, the mechanical properties, including tensile stress at peak, tensile modulus, and izod impact strength were improved.

Dimensional stability of lotus leaf-like nanostructure superhydrophobic bamboo by modification using xylan

Xylan extracted from corncobs was used to modify bamboo and to improve its dimensional stability. A lotus leaf-like surface was prepared on the modified bamboo using a fresh lotus leaf and polydimethylsiloxane (PDMS) as the template and seal via soft lithography. The dimensional stability of bamboo was tested via anti-shrinkage efficiency (ASE), moisture excluding efficiency (MEE), weight percent gain (WPG), and its superhydrophobic property. The microstructures of lotus-like bamboo surface were analyzed via water contact angle (WCA), scanning electron microscopy, and atomic force microscopy (AFM). The study found that with increasing mass fraction of xylan content, the anti-swelling property and WPG of modified bamboo increased accordingly. When the mass fraction of xylan was 10%, its WPG was the largest (2.21%), and xylan had a better compatibilization effect on bamboo. The dimensional stability of bamboo was improved to a certain extent by xylan. Moreover, the anisotropy and superhydrophobicity of the lotus leaf-like bamboo treated by xylan were noticeably improved after modification, such that the WCA of the transverse, radial, and tangential sections were 157.5º, 145.5º, and 137.5º, respectively. This research lays a foundation for studies of dimensional stability of bamboo and the mechanism of modification to achieve hydrophobic properties.

The synergistic effect of fluorosilicone and silica towards the compatibilization of silicone rubber and fluoroelastomer based high performance blend

Fluoroelastomer and silicone rubber lie in the two different poles of elastomer family in terms of polarity. Hence, combining them in a single material and making it as at least technologically compatible substance is a great challenge. In this article, the compatibilization effect of fluorosilicone rubber (block copolymer) (trifluoropropylpolydimethylsiloxane) with various loading of modified silica filler on the novel advanced polymer architecture based fluoroelastomer (copolymer of hexafluoropropylene, vinylidene fluoride, and tetrafluoroethylene) and silicone rubber (poly methylvinylsiloxane) blends has been studied in details. The mechanical properties show significant improvement at room temperature (13%) and remarkably more at high temperature (54%) for the compatibilized system. Tan delta peak shifting in DMA study indicates better compatibilization for 2.5 phr loading of fluorosilicone and 15 phr loading of silica at 50/50 blend ratio. The reduction in domain size (from ⁓3 μm to ⁓200 nm) of the fluorocarbon phase by the synergistic effect of silica and fluorosilicone proves the decrease in interfacial tension and better compatibilization. This blend can be judiciously applicable in the sealing system as oil and fuel resistant O-rings and gaskets for a very wide range of temperature.

Enhancing the dielectric properties of compatibilized high-density polyethylene/calcium carbonate nanocomposites using high-density polyethylene-g-maleic anhydride

High-density polyethylene (HDPE) and nanoparticles of calcium carbonate (NCC) have been mixed via melt blending technique using different ratios of NCC as nanofiller and high-density polyethylene-g-maleic anhydride (HDPE-g-MA) as a compatibilizer. The combined effect of NCC as well as HDPE-g-MA concentrations on the breakdown strength and dielectric spectroscopy performance of HDPE was investigated. According to the American Society for Testing and Materials (ASTM) standard, the ac breakdown voltage of such nanocomposites was measured at constant 500 V/s ramp. The ac breakdown voltage was enhanced by 8.2% for HDPE/ 2wt% NCC and reached 21% in the presence of 1 wt% HDPE-g-MA which increases the efficiency of NCC dispersion. The surface morphology of synthesized HDPE/NCC and HDPE/NCC/HDPE-g-MA nanocomposites was characterized by field-emission scanning electron microscopy (FE-SEM). FE-SEM images showed an enhanced dispersion of NCC that may be due to good adhesion between NCC and HDPE under the compatibilization effect of HDPE-g-MA. Fourier-transform infrared (FTIR) analysis showed chemical interaction between HDPE-g-MA and stearic acid on the surface of NCC and physical entanglement among HDPE and HDPE-g-MA. Dielectric constant (e′) and tangent loss (tan δ) were measured under different applied frequency values from 1 kHz to 1 MHz.

Effect of triblock copolymers based on liquid natural rubber and low molecular weight poly(lactic acid) on physical properties of poly(lactic acid)/natural rubber blend

Triblock copolymers of poly(lactic acid) (PLA) and natural rubber (NR) (PLA–NR–PLA) with different lengths of PLA end blocks were produced from hydroxyl-terminated liquid natural rubber (HTLNR) and low molecular weight PLA (pre-PLA). The HTLNR with a number-average molecular weight $$(\bar{M}_{\text{n}} )$$ ~ 28,000 g/mol obtained from photochemical degradation of NR and pre-PLA with varying molecular weight ( $$\bar{M}_{\text{n}}$$ ~ 3000, ~ 6500, ~ 9700 g/mol) was subjected to condensation polymerization. The compatibilizing effect of copolymers on the physical properties of the PLA/NR blend was studied using PLA/NR/PLA–NR–PLA blend ratios of 90/10/0, 90/9/1, 90/8/2 and 90/7/3 percent by weight (wt%). From the tensile testing results, elongation at break of the blends increased with an increase in the amount of triblock copolymer and with the length of the PLA end block. The blend without the copolymer showed elongation at break of 60.54%, whereas the blend with 3 wt% of PLA–NR–PLA prepared from pre-PLA with $$\bar{M}_{\text{n}}$$ of ~ 9700 g/mol showed elongation at break of 199.38%. This was about a 300% increase. The highest impact strength of 79.58 kJ/m2 (400% higher than neat PLA) was also found for the blend containing 3 wt% of PLA–NR–PLA with the longest PLA end block. A reduction in the diameter and well dispersion of the rubber particles in the PLA matrix were seen in micrographs taken with a scanning electron microscope. In general, after the addition of PLA–NR–PLA into a PLA/NR blend, the Tg of NR phase shifted to a higher temperature, whereas the Tg of the PLA phase decreased. The PLA–NR–PLA triblock copolymer with the longest PLA end block is possibly used as an effective compatibilizer for the PLA/NR blend.

Reactive Comb Polymer Compatibilized Immiscible PVDF/PLLA Blends: Effects of the Main Chain Structure of Compatibilizer.

The compatibilizer with double comb structure has a superior compatibilizing effect for immiscible polymer blends due to the symmetrical structure on both sides of main chains. Extensive study related to the architectural effects of compatibilizer on the compatibilization has mainly focused on the side chains. We investigated the influence of the compatibilizer-main-chain structure on the compatibilizing effect for immiscible poly(vinylidene fluoride)/poly(L-lactic acid) (PVDF/PLLA) blends. Two reactive-comb compatibilizers with polystyrene (PS) and polymethylmethacrylate (PMMA) as main chains and PMMA as the side chains have been synthesized. PS is immiscible with both PLLA and PVDF, while PMMA is miscible with PVDF. It was found that both compatibilizers can improve the compatibility between the PLLA and PVDF, with different compatibilization effects. In the PVDF/PLLA (50/50) blends, 1 wt.% poly(styrene-co-glycidyl methacrylate)-graft-poly(methyl methacrylate) (RC–SG) tuned the morphology from the droplet-in-matrix structure to the co-continuous structure, while the blends with poly(methyl methacrylate-co-glycidyl methacrylate)-graft-poly(methyl methacrylate) (RC–MMG) kept the sea-island structure with even 3 wt.% loading. Moreover, RC–SG induces a wider co-continuous interval range than RC–MMG. The co-continuous structure obtained by RC–SG was also more stable than that by RC–MMG. It was further found that RC–SG-compatibilized PVDF/PLLA blends exhibit higher mechanical properties than the RC–MMG-compatibilized blends.