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• Strength, toughness and hydrolysis resistance of fibrous PGA/PBAT are simultaneously improved. • Enhanced chain entanglement restricts the chain relaxation during drawing process. • Poor chain mobility results in more extended chains being transformed into rigid amorphous fraction. The application of poly(glycolic acid) (PGA) is limited by its inherent brittleness and easy to hydrolysis. Herein, we demonstrate an effective strategy to make fibrous PGA/poly (butylene adipate-co-terephthalate) (PBAT) blends with high strength, toughness and better hydrolysis resistance by reactive compatibilization and subsequent solid-state drawing. The enhanced chain entanglement due to the compatibilization restricts the chain relaxation during drawing process, leading to a predominance of stress-induced orientation. Meanwhile, it also facilitates the immobilization and transformation of extended chains into rigid amorphous fraction (RAF). As a consequence, the combination of strong interfacial bonding, high orientation and abundant RAF results in superior comprehensive properties of the fibrous PGA/PBAT blends, e.g., the drawn compatibilized PGA/PBAT exhibit a tensile strength as high as 700 MPa and a tensile toughness of 385 MJ/m3. Moreover, the tensile strength retention of the drawn compatibilized PGA/PBAT is 20 % higher than uncompatibilized sample after hydrolysis for 5 days. Therefore, this work provides a feasible strategy to make robust and durable fibrous PGA-based blends, which may broaden the application range of PGA. [Display omitted] [ABSTRACT FROM AUTHOR]

As an emerging bioplastic, poly(glycolic acid) (PGA) possesses excellent bio-compostability, gas barrier properties, mechanical strength and heat resistance. However, the inherent brittleness and inferior melt-strength of PGA severely limits its processability and application possibilities. In the present contribution, a two-step reactive melt blending of PGA and poly(butylene adipate-co-terephthalate) (PBAT) with epoxy functionalized copolymer (ethylene-methyl acrylate-glycidyl methacrylate) (EMAG) as compatibilizer was investigated to solve these shortcomings. The EMAG was first blended with PBAT and then with PGA to in-situ form PGA-g-EMAG-g-PBAT copolymers. These copolymers selectively locate at the interface between PGA and PBAT, which effectively improved the interfacial adhesion and the compatibility. Consequently, the PGA/(PBAT/EMAG) blends with 1 wt % EMAG exhibited high elongation at break (45 ± 4%) and a notched impact strength (14.4 ± 1.6 kJ/m2) respectively, which is about 1100% and 410% higher than that of PGA. Meanwhile, the viscosity and storage modulus of the PGA/(PBAT/EMAG) blends at 50.1 Hz were enhanced by 130% and 230% compared with PGA. This work provides a facile route to fabricate PGA-based blends with excellent toughness and melt strength, which could open up new possibilities for the application of PGA materials. [Display omitted] • Bio-compostable poly(glycolic acid)-based blends were prepared by reactive melt blending. • Two-step blending processes was used to control the interfacial localization of in-situ grafted copolymers. • Interface-localized copolymers markedly enhance interfacial adhesion and compatibility between PGA and PBAT. • PGA/(PBAT/EMAG) blends exhibited much superior toughness and melt strength than PGA. [ABSTRACT FROM AUTHOR]

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 M 3 G 1 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. [ABSTRACT FROM AUTHOR]

Nano-sized starch (NSt) was reported as reactive filler to reinforce ethylene-co-vinyl acetate rubber (EVM) by using epoxy-functionalized EVM (GMA-EVM) as compatibilizer together with 3-(2-aminoethylamino) propyl dimethoxy methyl silane (KH602). This resulted in EVM/GMA-EVM/NSt nanocomposites having significant improved properties. The improvement is attributed to the small starch particle size and chemical compatibilization. The tensile strength ( Ts ) was increased from 9.2 to 18.7 MPa when 20 phr (per hundred rubber by weight) of the GMA-EVM compatibilizer is incorporated. Compared to EVM/NSt, the EVM/GMA-EVM/NSt nanocomposites possess stronger interfacial interaction between fillers and the matrix according to morphology and crosslink density analysis. Besides the crosslink of EVM and GMA-EVM chains created by dicumyl peroxide (DCP), under the aid of KH602, extra chemical bonding was generated between: (a) GMA-EVM chains, (b) GMA-EVM and NSt. Thus, strong reinforcement of EVM was obtained. These interesting results provide a new insight to make robust rubbers which may create new applications for rubbers and natural fillers. [ABSTRACT FROM AUTHOR]

The wide application of fully biodegradable polylactic acid/polybutylene terephthalate (PLA/PBAT) blends in environmentally friendly packaging were limited because of poor compatibility. Normal compatibilizers suffer from poor thermal stability and non-biodegradability. In this work, epoxy copolymer (MDOG) with different molecular structures were made of 2-methylene-1, 3-dioxoheptane, and glycidyl methacrylate as raw materials by free radical copolymerization. MDOG copolymers have good biodegradability and a high thermal decomposition temperature of 361 °C. The chemical reaction of the epoxy groups in MDOG with PLA and PBAT during the melting reaction improved the interfacial bonding by decreasing the particle size of PBAT. Compared to the PLA/PBAT blends, the tensile strength and fracture toughness of PLA/PBAT/MDOG blends were enhanced to 34.6 MPa and 115.8 MJ/m3, which are 25 % and 81 % higher, respectively. As a result, this work offers new methods for developing thermally stable and biodegradable compatibilizers, which will hopefully promote the development of packaging industry. • MDOG with biodegradability and thermal stability was synthesized as reactive compatibilizers. • Super-toughed and biodegradable PLA/PBAT blends were prepared by reactive melt blending. • New ideas for design of biodegradable reactive compatibilizers for efficient in-situ compatibilization. [ABSTRACT FROM AUTHOR]

• PGMA with different molecular weight was synthesized as reactive compatibilizers. • Super-toughed and biodegradable PLA/PBAT blends were prepared by reactive melt blending. • Interface-localized copolymers markedly enhance interfacial adhesion and compatibility between PLA and PBAT. • New ideas for the design of efficient compatibilizers for biodegradable polyesters were provided. Poly (glycidyl methacrylate) (PGMA) with different molecular weight (M w) were synthesized and used as reactive compatibilizers to prepare super-toughed and biodegradable polylactide/poly (butylene adipate-co-terephthalate) (PLA/PBAT) blends. The epoxy group of PGMA can in-situ react with the end groups of PLA and PBAT, thus improving the interfacial adhesion between PLA and PBAT by forming PLA-g-PBAT copolymers. The effects of M w and content of PGMA on phase morphology and physical properties of the PLA/PBAT blends were systematically investigated. The M w takes an important role in its dispersion between the PLA and the PBAT phases, and consequently influences the mechanical performance. Interestingly, the PBAT domain size in the PLA matrix decreased from 3.7 μm to 1.7 μm after incorporation of even 0.5 wt% PGMA with a M w of 44 kDa, and the in-situ improved compatibility leading to that the tensile strength and elongation at break of the PLA/PBAT blends increased by 35% and 87%, respectively. On the contrary, the size of the PBAT domains increased to > 5 μm and the mechanical properties of the PLA/PBAT blends decrease obviously with the same content but a higher M w (90 kDa) of PGMA, because the higher Mw PGMA dispersed and reacted solely with the PLA matrix, and the enhanced melt viscosity of the PLA matrix could result in a non-uniform dispersion of the PBAT. Therefore, this work provides new insight in designing and preparation of efficient compatibilizers for biodegradable polyesters. [ABSTRACT FROM AUTHOR]