Reactive Compatibilization Research Articles

Compatibilizing Biodegradable Poly(lactic acid)/polybutylene adipate-co-terephthalate Blends via Reactive Graphene Oxide for Screw-Based 3D Printing.

Vinyl-functionalized graphene oxide (VGO) was used as a reactive compatibilizer to prepare poly(lactic acid)/polybutylene adipate-co-terephthalate (PLA/PBAT) blends. The linear rheological and scanning electron microscopy results confirmed that the VGO nanosheets were quite efficient in compatibilizing PLA/PBAT blends. The size of the PBAT dispersed phase was remarkably decreased in the presence of VGO nanosheets. Moreover, the VGO nanosheets exhibited strong nucleating effects on the crystallization process of PLA. The crystallinity of PLA component in the compatibilized blend with various VGO nanosheets was higher than 40%, upon the cooling rate of 20 °C/min. The prepared PLA/PBAT pellets were applied to 3D printing, using a self-developed screw-based 3D printer. The results showed that all the prepared PLA/PBAT blend pellets can be 3D printed successfully. The notched Izod impact test results showed that, in the presence of VGO, an increase of at least 142% in impact strength was achieved for PLA/PBAT blend. This could be attributed to the compatibilizing effect of the VGO nanosheets. Thus, this work provides a novel way to prepare tough PLA-based materials for 3D printing.

Toward High Strength, Ductility, and Barrier Performance for Poly(glycolic acid)/Poly(butylene adipate-co-terephthalate) Green Films through Reactive Compatibilization and Biaxial Drawing

Toward High Strength, Ductility, and Barrier Performance for Poly(glycolic acid)/Poly(butylene adipate-<i>co</i>-terephthalate) Green Films through Reactive Compatibilization and Biaxial Drawing

Synthesis, Recycling and High‐Throughput Reprocessing of Phase‐Separated Vitrimer‐Thermoplastic Blends

AbstractPhase‐separated polymer blends including a transesterification vitrimer and polypropylene are synthesized from widely available precursors through reactive processing. It is shown that proper formulation during the process including a viscosity modifier of the vitrimer precursors and a reactive interface compatibilizer yields well‐dispersed vitrimer phases with fractions up to 75 wt.% in the polypropylene phase. These vitrimer blends can be easily reprocessed by multiple shredding‐injection cycles and processed in high‐shear conditions through capillary rheometry. Rheological analyses reveal that a percolating dynamic network is formed across the vitrimer domains. It breaks apart during high shear reprocessing of the material and dynamically reforms after thermal annealing of the blends. It therefore ideally combines the mechanical and high‐throughput (re)processing properties of the thermoplastic matrix minor phase with the chemical, thermomechanical, and dynamic properties of the vitrimer major phase. This work illustrates the decoupling of processing at high shear rates enabled by the polypropylene processing aid from the kinetics of dynamic exchanges of the vitrimer phase and thermomechanical properties at the service temperature of the blends.

Correction to: Toughening and Shape Memory Effect on PLA/Copolymers Blends Produced by Simultaneous Dynamic Vulcanization and Reactive Compatibilization

Correction to: Toughening and Shape Memory Effect on PLA/Copolymers Blends Produced by Simultaneous Dynamic Vulcanization and Reactive Compatibilization

Compatibilization of polylactide/poly(butylene adipate-co-terephthalate) blends with epoxidized natural rubber as a reactive compatibilizer

In this study, the effectiveness of using epoxidized natural rubber (ENR) to compatibilize blend of polylactide (PLA) with poly(butylene adipate-co-terephthalate) (PBAT) has been examined. Interfacial interaction analysis revealed that ENR had higher affinity with PBAT. To achieve better compatibility, a two-step procedure was developed involving blending PLA with ENR first, followed by blending with PBAT. Graft copolymers consisting of PLA, ENR, and PBAT were formed through melt blending, resulting in improved compatibility of PLA blends with PBAT. As the ENR content increased, the dispersed PBAT phase exhibited a gradual reduction in particle size. After compatibilization, the blends showed significantly improved toughness. Ternary PLA/PBAT/ENR blend containing 2 wt% ENR exhibited a drastic increase in break strain, measuring at 589%. This was approximately 2.7 times greater than the break strain of the binary blend PLA/PBAT (221%). The mechanism for tensile toughening of the PLA/PBAT/ENR ternary blends was interfacial bonding cavitation-initiated matrix plastic deformation. Compatibilization of PLA/PBAT blends with ENR is with great promise as it doesn’t compromise the biobased carbon content and sustainability of the materials.

Evaluation of shape memory effect in PLA/copolymers blends

AbstractIn this work, polylactic acid (PLA)/copolymer blends were prepared by melt blending. Ethylene‐glycidyl methacrylate (E‐GMA) and ethylene‐butyl acrylate‐maleic anhydride (EBA‐MAH) functional block copolymers were used. A ternary blend of PLA/E‐GMA/EBA‐MAH was also studied. FTIR analyses evidenced the occurrence of reactive compatibilization of E‐GMA and EBA‐MAH with PLA in the binary blends due to the reactivity of the GMA and MAH functional groups with the terminal hydroxyl and carboxyl groups of PLA. Rheological measurements evidenced the occurrence of cross‐link reactions between E‐GMA and EBA‐MAH copolymers in the ternary blend. Three distinct morphologies were observed in the blends: PLA/E‐GMA exhibited a sea‐island structure, PLA/EBA‐MAH exhibited a co‐continuous structure, and PLA/E‐GMA/EBA‐MAH exhibited a semi‐interpenetrating polymer network (SIPN) structure. The shape memory effect (SME) of PLA and PLA/copolymers blends was evaluated by three different methods: fold‐deploy, tension, and torsion. Fold‐deploy tests were conducted in a water bath, whereas the tension and torsion tests were conducted using a rheometer. All methods proved to be effective; however, some precautions must be taken to choose the most suitable test for a given purpose, which is thoroughly discussed in this work. The SME of PLA was enhanced through the incorporation of the copolymers. Blending PLA with E‐GMA, EBA‐MAH, and E‐GMA/EBA‐MAH copolymers increased its shape recovery from 32% to 84%, 79.2%, and 80%, respectively, while its shape fixity remained around 100%.

Strong synergistic toughening and compatibilization enhancement of carbon nanotubes and multi-functional epoxy compatibilizer in high toughened polylactic acid (PLA)/poly (butylene adipate-co-terephthalate) (PBAT) blends

Different carbon nanotubes (CNTs) contents on high-toughness polylactic acid (PLA)/poly (butylene adipate-co-terephthalate) (PBAT) blends were prepared by one-step melt blending using multifunctional epoxy oligomers (ADR) as reactive compatibilizer. During reactive blending, the PLA or PBAT chains were grafted onto the CNTs by allowing the carboxyl or hydroxyl groups to react with epoxy groups and form a branched CNTs-based copolymer. The branched copolymer at the interface between PLA and PBAT was dispersed through emulsion to improve the polymer–polymer or polymer–nanoparticle entanglement between the molecular chains. Interfacial adhesion, interface layer stability, and system viscoelasticity and compatibility were improved as indicated by rheological curves and dynamic mechanical analysis. The strength and toughness of the sample were simultaneously improved by the addition of CNTs and ADR. The impact strength reached 35.3 kJ/m2, which was approximately 7 times that of the PLA/PBAT blend, and the tensile strength was also increased from 33.6 MPa to 42.8 MPa. The properties of PLA/PBAT blend synergistically modified by ADR and CNTs were obviously better than those of PLA/PBAT blend modified by ADR or CNTs. The toughening synergistic effect of ADR and CNTs on PLA/PBAT was observed with efficiency reaching 3.05. With the further understanding of the toughening mechanism, the branched CNTs-based copolymers and CNTs clusters induce a synergistic effect, which increased the interfacial adhesion and ability of energy dissipation and stress transmission.

Compatibilization of immiscible polymer blends by reactive polymer grafted graphene with interfacial crosslinking

AbstractWe investigate reactive compatibilization by applying two multifunctional polymers grafted on a graphene surface, which leads to crosslinked interphase at immiscible polymer blends. Reactive compatibilizer‐grafted graphene (RCG) nanoparticles were synthesized through esterification and amidation reactions between oxidative groups of graphene oxide and reactive multifunctional groups of polymers. Polymer blends of polyisoprene (PI) and polydimethysiloxane (PDMS) with PI:PDMS ratio of 30:70 or 70:30 and RCG nanoparticle loadings from 0.1 and 1 wt% were evaluated by optical microscopy and rheometry. The results indicated that the blend with 0.1 wt% RCG showed unusual characteristics including nonspherical and bridged droplets, while those containing 1 wt% RCG showed usual droplet‐matrix morphology. The rheological results are also asymmetric: the blend with 0.1 wt% RCG displayed gel‐like behavior in the dynamic oscillatory tests, high viscosity, slow interfacial relaxation during startup shear flow, and divergence in the transient stress response due to coalesced and bridged droplets. However, the latter blend containing 1 wt% RCG reveals liquid‐like behavior, low viscosity, and convergence in the transient stress response due to stabilized droplet‐matrix morphology. Overall, it was suggested that these asymmetries are attributable to interfacial crosslinked interphase formed through an in‐situ reaction between multifunctional polymers grafted on graphene sheets.

Preparation of high‐performance poly(butylene adipate‐co‐terephthalate)/thermoplastic starch compounds with epoxidized soybean oil as compatibilizer

AbstractBiodegradable poly(butylene adipate‐co‐terephthalate) (PBAT) has excellent processing and mechanical properties. However, PBAT is expensive and its relatively slow biodegradation rate limits its wide application. In this paper, PBAT/thermoplastic starch (TPS) complexes were prepared by a two‐step process using epoxidized soybean oil (ESO) as a reactive compatibilizer. The compatibilizing ability of ESO was investigated by FT‐IR and GPC. Results showed ESO could form a chemical bonding interface with PBAT and TPS. Compared to PBAT/TPS, tensile strength, elongation at break and tear strength of PBAT/TPS/5%ESO composites increased by 84%, 53%, and 68%, respectively. The optical transparency of the PBAT/TPS/5%ESO film improved by 6% compared to the PABT/TPS film. This research offers a viable solution for the preparation of high performance, green PBAT/TPS complexes.

Super toughened blends of poly(lactic acid) and poly(butylene adipate-co-terephthalate) injection-molded foams via enhancing interfacial compatibility and cellular structure

Biodegradable poly(lactic acid) (PLA) foams have drawn increasing attention due to environmental challenges and petroleum crisis. However, it still remains a challenge to prepare PLA foams with fine cellular structures and high impact property, which significantly hinders its widespread application. Herein, phase interface-enhanced PLA/ poly(butylene adipate-co-terephthalate) (PBAT) blend foam, modified by a reactive compatibilizer through a simple reactive extrusion, was produced via a core-back foam injection molding technique. The obtained PLA blend foams displayed an impact strength as high as 49.1 kJ/m2, which was 9.3 and 6.4 times that of the unmodified PLA/PBAT blend and its corresponding foam, respectively. It proved that the interfacial adhesion and cell size both strongly affected the impact strength of injection-molded PLA/PBAT foams, and two major conclusions were proposed. First, enhancing interfacial adhesion could cause a brittle-tough transition of PLA/PBAT foams. Additionally, for foams with high interfacial adhesion, small cell size (<12 μm) was more favorable for the stretching of cells and extension of the whitened region in comparison with big cell size (cell size >60 μm), leading to the drastic toughening of PLA blends. This study provides a feasible, industrially scalable and practical strategy to prepare super toughened and fully biodegradable PLA materials.

Highly toughened poly (lactic acid)/poly (butylene adipate-terephthalate) blends in-situ compatibilized by MMA-co-GMA copolymers with different epoxy group content

Poor compatibility limits the wide application of biodegradable poly (lactic acid)/poly (butylene adipate-terephthalate) (PLA/PBAT) blends in packaging industry. How to prepare compatibilizers with high efficiency and low cost by simple methods is a challenge. In this work, methyl methacrylate-co-glycidyl methacrylate (MG) copolymer with different epoxy group content are synthesized as reactive compatibilizers to resolve this issue. The effects of glycidyl methacrylate and MG contents on phase morphology and physical properties of the PLA/PBAT blends are systematically investigated. During melt blending, MG migrates to the phase interface, and then grafts with PBAT to form PLA-g-MG-g-PBAT terpolymers. When the molar ratio of MMA and GMA in MG is 3:1, the reaction activity of MG with PBAT is the highest and the compatibilization effect is the best. When the M3G1 content is 1 wt%, the tensile strength and the fracture toughness are increased to 37. 1 MPa and 120 MJ/m3, which increase by 34 % and 87 %, respectively. The size of PBAT phase decreases from 3.7 μm to 0.91 μm. Therefore, this work provides a low-cost and simple method to prepare the compatibilizers with high efficiency for the PLA/PBAT blend, and provides a new basis for the design of epoxy compatibilizers.

Toughening and Shape Memory Effect on PLA/Copolymers Blends Produced by Simultaneous Dynamic Vulcanization and Reactive Compatibilization

Toughening and Shape Memory Effect on PLA/Copolymers Blends Produced by Simultaneous Dynamic Vulcanization and Reactive Compatibilization

Reactive Janus Particle Compatibilizer with Adjustable Structure and Optimal Interface Location for Compatibilization of Highly Immiscible Polymer Blends.

Highly immiscible blend materials with distinctive and excellent properties play a key role in meeting the application needs, especially in extreme environments, and reactive nanoparticles are used to increase the interface adhesion and optimize the morphology of highly immiscible blending. However, these reactive nanoparticles tend to aggregate and even agglomerate during reactive blending, which significantly deteriorates their compatibilization efficiency. Herein, reactive Janus particles with the epoxy group and various siloxane molecular long chain grafting ratios (E-JP-PDMS) were synthesized using SiO2@PDVB Janus particles (JP) and used as compatibilizers for polyamide and methyl vinyl silicone elastomer (PA/MVQ) blends, which were highly immiscible. The effects of the structure of E-JP-PDMS Janus nanoparticles on their location at the interfaces between the PA and MVQ as well as their compatibilization efficiency for the PA/MVQ blends were investigated. The location and dispersion of E-JP-PDMS at the interfaces were improved by increasing the PDMS content in E-JP-PDMS. The average diameter of the MVQ domains of the PA/MVQ (70/30, w/w) was 79.5 μm and was reduced to 5.3 μm in the presence of 3.0 wt % of the E-JP-PDMS with 65 wt % PDMS. As a comparison, it was 45.1 μm in the presence of 3.0 wt % of a commercial compatibilizer (ethylene-butylacylate-maleic anhydride copolymer, denoted as EBAMAH), which provides a guideline for the design and preparation of efficient compatibilizers for highly immiscible polymer blends.

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

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

The Effect of Epoxidized Soybean Oil on the Physical and Mechanical Properties of PLA/PBAT/PPC Blends by the Reactive Compatibilization.

Poly (lactic acid) (PLA)/poly (butylene adipate-co-terephthalate) (PBAT)/poly (propylene carbonate) (PPC) multi-phase blends were prepared by melt processing technique under the presence of compatibilizer with various composition. The effect on the physical and the mechanical property with/without ESO was characterized with spectrophotometric analysis, mechanical properties, thermal properties, rheological properties and barrier properties, and the structure-properties relationship was assessed. ​​The functional groups of PPC were found to effective to improve an interaction with carboxyl/hydroxyl group of PLA/PBAT binary blends to enhance the mechanical and physical properties on multi-phase blend system. The presence of PPC in PLA/PBAT blend affected the reduction of voids on the interface phase resulting in enhancing the oxygen barrier properties. With addition of ESO, the compatibility of ternary blend was found to be enhanced since the epoxy group of ESO reacted with the carboxyl/hydroxyl group of PLA, PBAT, and PPC, and under the condition with critical content of 4 phr of ESO, the elongation behavior dramatically increased as compared to that of blends without ESO while affecting reduction of oxygen barrier properties. The effect of ESO as a compatibilizer was clearly observed from the overall performances of ternary blends, and the potential feasibility of the PLA/PBAT/PPC ternary blends as packaging materials was confirmed at this study.

Crystallization behavior analysis and reducing thermal shrinkage of poly(lactic acid) miscibilized with poly(butylene succinate) film for food packaging

AbstractPoly(lactic acid) (PLA) incorporated with poly(butylene succinate) (PBS) through in situ reactive blending is proposed to retard thermal shrinkage. Succinic anhydride (SA) with varied contents (0.01–0.5 phr) was used as a reactive compatibilizer to enhance miscibility between PLA and PBS phases. The success of PLA chemically bound with PBS chains through simple esterification to form PLA‐SA‐PBS phase is confirmed and quantified using an X‐ray photoelectron spectroscopy technique. The binding energy intensity ratio of ester and hydrocarbon in the PLA/PBS/SA blend with 0.5 phr SA increases for two‐fold, as compared to the PLA/PBS blend. The good interfacial adhesion of PLA and PBS phases is achievable with SA content up to 0.1 phr. In addition, the PLA‐SA‐PBS molecules preferentially support crystallization of PBS phase with increased degree of crystallinity (Xc,PBS) by ~15%. These enhanced homogeneity of PLA/PBS/SA blend and high Xc,PBS trigger the increased tensile strength to 50 MPa, and substantially reduced oxygen permeation coefficient approximately 10 times. Remarkably, the interpenetration of PLA‐SA‐PBS phase in amorphous PLA region coexisting with uniformly dispersed PBS crystals inhibits the PLA chain relaxation and deformation at elevated temperatures, leading to maintaining dimensional stability of PLA/PBS/SA films without shrinkage at 100°C.

Improved compatibility of PLA/Starch blends with Binary functional monomers through UV-induced reactive extrusion

In this work, we chose starch as a biomass nucleating agent for PLA to enhance the crystalline properties without affecting the biodegradability of the composite. Under the synergistic effect of glycidyl methacrylate (GMA) and trimethylpropane triacrylate (TMPTA), biodegradable PLA/Starrch composites were prepared by a unique UV-induced reactive extrusion technique. GMA was grafted onto PLA with the help of TMPTA and the modified PLA enhanced compatibility with starch via epoxidation reaction during extrusion. The rheological properties, mechanical properties, and crystallization behavior of PLA/Starch composites were researched. The rheological and FITR results demonstrated that the introduction of GMA/TMPTA in PLA/Starch blends not only promoted the reactive compatibilization of PLA with starch but also produced a certain degree of chain branching effect. Meanwhile, starch provides heterogeneous nucleation sites for PLA crystallization, which improved the crystallization performance of PLA. In addition, the mechanical properties of the composite were improved. Compared with pure PLA, the tensile stress of the composite was increased by 116% and the elongation at break was increased by 118%. In summary, this work provides a new strategy for the preparation of PLA/starch composites, which is expected to expand the application of PLA in the packaging field.

Fully biobased poly(lactic acid)/lignin composites compatibilized by epoxidized natural rubber

Biobased poly(lactic acid)/lignin (PLA/lignin) composites are limited by poor mechanical properties resulted from poor compatibility and low interfacial adhesion. Herein, we reported a novel approach to improve compatibility and interfacial adhesion of PLA/lignin composites via reactive compatibilization with epoxidized natural rubber (ENR) as a compatibilizer. Interfacial tension calculation indicated that lignin tended to act as interfacial phase between PLA and ENR, but morphology analysis demonstrated lignin was wrapped with a layer of ENR and dispersed in PLA matrix, which was attributed to the interfacial reaction of ENR with both PLA and lignin. The interfacial reaction was confirmed by Fourier transform infrared spectroscopy. The compatibility and interfacial adhesion between PLA and lignin were improved significantly by incorporation and increase in the content of ENR, as evidenced by the reduced interfacial gaps, blurry phase boundaries, and enhanced elastic response. As such, the mechanical properties of PLA/lignin composites were enhanced significantly. The tensile strength and elongation at break of PLA/lignin (W/W, 80/20) were improved by 15 % and 77 %, respectively, with the incorporation of only 1 wt% ENR. We believe this approach to compatibilize PLA/lignin composites is promising because it would not require costly modification of lignin and would not compromise the sustainability of composites.

SbB-g-GMA Copolymer as a Dual Functional Reactive Compatibilizer and Impact Modifier for Potential Recycling of PET and PS via Melt Blending Approach

SbB-g-GMA Copolymer as a Dual Functional Reactive Compatibilizer and Impact Modifier for Potential Recycling of PET and PS via Melt Blending Approach

High impact strength of aliphatic polyketone/polyamide 6 blends induced by a chemical reaction

Compatibility and physical properties of aliphatic polyketon (PK)/polyamide 6 (PA6) blend were investigated. The PK and PA6 showed high adhesion strength and thus impact strength of PK/PA6 blends was very high. It was observed that PK-PA6 copolymers are formed by a chemical reaction between the two polymers and the copolymers act as a reactive compatibilizer in the PK/PA6 blends. The presence of the PK-PA6 copolymer was confirmed by FTIR analysis. The adhesion strength between PK and PA6 was very high compared to a typical incompatible polymer pair. PA6 investigated herein has two end groups, NH2 and carboxylic acid. We also adopted end-capped PA6 that has two carboxylic acid end groups. The adhesion strength and impact strength of the PK/end-capped PA6 blends was much lower than that of PK/PA6 blends. More importantly, the PK-PA6 copolymer was not formed in the PK/end-capped PA6 blends. Thus, it was concluded that the chemical reaction occurs between the carbonyl of PK and the primary amine end group of PA6. Due to the high impact strength of PK/PA6 blends, possible applications could be automotive parts where higher impact strength is required.