Effect of triphenyl phosphite as a reactive compatibilizer on the properties of poly(L-lactic acid)/poly(butylene succinate) blends

Reactive blending is an innovative method for the improvement of compatibility of polymer blend. In this work, poly ( _L-lactic acid) and poly (butylene succinate) (PLLA/PBS) blends were prepared by melt blending to ameliorate the toughness of PLLA. Triphenyl phosphite (TPP) was introduced into the PLLA/PBS blends (80/20 by weight) to enhance their compatibility via reactive blending. The effects of TPP on the morphology and properties of PLLA/PBS blends were studied systematically. The increased torque during melt blending demonstrated that the compatibilizer successfully reacted with PLLA and PBS. The mechanical properties of the blends were exceedingly improved only with 0.5 wt% TPP. A reduction tendency of size of the dispersed phase was observed due to the improvement of compatibility. The DSC and DMA results indicate that the T _g of PLLA decreased at a slow rate with the increasing content of TPP. This work provided a simple approach for preparing a kind of high toughed PLLA material. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48646.     

Reactive compatibilization of poly(l‐lactide)/poly(butylene succinate) blends through polyester maleation: from materials to properties

The melt blending of poly(l ‐lactide) (PLLA) with biodegradable poly(butylene succinate) (PBS) is considered with a view to fine‐tuning its mechanical properties and its degradability. For this purpose, both maleic‐anhydride‐grafted PLLA (PLLA‐g‐MA) and maleic‐anhydride‐grafted PBS (PBS‐g‐MA) were prepared and used as reactive compatibilizers. The influence of PBS melt viscosity on the morphology and mechanical properties of PLLA/PBS blends was studied. Interestingly, the blending of low viscosity PBS with PLLA allows PLLA to be toughened while the use of high viscosity PBS led to PLLA/PBS blends exhibiting co‐continuous morphology. The nanostructure of the co‐continuous blends may be tuned through the joint action of organo‐modified clays and reactive compatibilizers. The effect of PBS on PLLA degradability was also investigated. The accelerated weathering testing of blends reveals that such combination of biodegradable polymers allows their degradability rate to be tailored. It is found that the addition of 20 wt% PBS to PLLA allows the molar mass loss fraction to be doubled after 425 h of testing. © 2014 Society of Chemical Industry     

Peculiar crystallization kinetics of biodegradable poly(lactic acid)/poly(propylene carbonate) blends

Binary blends of poly(lactic acid) (PLA) and poly(propylene carbonate) (PPC) were found to display a peculiar crystallization kinetics. The two biodegradable polymers were blended by melt mixing, to obtain binary blends at various compositions. Temperature‐modulated calorimetry and dynamic‐mechanical analysis indicated that the blend components are partially miscible, and display two separate glass transitions, at temperatures intermediate to those of the plain polymers. Electron microscopy analysis disclosed the morphology of PLA/PPC blends, made of PPC‐rich particles finely dispersed within the PLA‐rich matrix. The possible establishment of interactions between the functional groups of the two polymers upon melt mixing has been hypothesized as the reason for partial miscibility and compatibility of the two biodegradable polymers. The PLA/PPC blends display good mechanical properties, with enhanced performance at rupture compared with plain PLA. Most importantly, the addition of PPC affects also the crystallization kinetics of PLA, since the more mobile PPC chains favor diffusion of the stiffer PLA chain segments towards the growing crystals, which fastens the spherulite growth rate of PLA. Such positive influence of an amorphous polymer on crystal growth rate has been demonstrated here for the first time in blends that display phase‐separation in the melt. POLYM. ENG. SCI., 55:2698–2705, 2015. © 2015 Society of Plastics Engineers     

The effect of poly(ethylene glycol) as plasticizer in blends of poly(lactic acid) and poly(butylene succinate)

The effect of polyethylene glycol (PEG) on the mechanical and thermal properties of poly(lactic acid) (PLA)/poly(butylene succinate) (PBS) blends was examined. Overall, it was found that PEG acted as an effective plasticizer for the PLA phase in these microphase‐separated blends, increasing the elongation at break in all blends and decreasing the T_g of the PLA phase. Significant effects on other properties were also observed. The tensile strength and Young's modulus both decreased with increasing PEG content in the blends. In contrast, the elongation at break increased with the addition of PEG, suggesting that PEG acted as a plasticizer in the polymer blends. Scanning electron microscope images showed that the fracture mode of PLA changed from brittle to ductile with the addition of PEG in the polymer blends. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43044.     

Atactic poly(methyl methacrylate) blended with poly(3‐D(−)hydroxybutyrate): Miscibility and mechanical properties

Atactic poly(methylmethacrylate), aPMMA, was blended with poly(3‐D(−)hydroxybutyrate), PHB, up to a maximum composition of 25% of polyester, at 190°C in a Brabender‐like apparatus. The resulting blends quenched from the melt to room temperature were completely amorphous, and exhibited a single glass transition using DSC and DMTA, indicating miscibility of the components for this time–temperature history. Tensile experiments showed that at room temperature the 10/90 and 20/80 PHB/aPMMA blends exhibited higher values of strain at break, and slight decreases of the modulus and stress at break compared to neat aPMMA. The tensile energy at break was almost twice that of neat aPMMA. Tensile tests were also performed at 80°C, at which point the 25/75 and 20/80 PHB/aPMMA blends are above T_g, while the 10/90 and neat aPMMA are below T_g. The stress–strain curves obtained were functions of the physical state of the amorphous phase, and also depended on the difference between the test temperatures and T_g. In particular, comparing the neat aPMMA and the blends, decreases of the modulus and stress at break and a respectable increase in the strain at break were observed in the latter. Finally, the results were commented considering the thermal degradation of PHB in the melt during the blend preparation. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 746–753, 2000     

Morphology,dynamic mechanical,and electrical properties of bio‐based poly(trimethylene terephthalate) blends,part 2: Poly(trimethylene terephthalate)/poly(ether esteramide)/polycarbonate blends

Bio‐based poly(trimethylene terephthalate) (PTT) and poly(ether esteramide) (PEEA) blends were prepared by melt processing with varying weight ratios (0–20 wt %) of polycarbonate (PC). The blends were characterized by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), polarized light microscopy (PLM), and transmission electron microscopy (TEM). Electrostatic performance was also investigated for those PTT blends since PEEA is known as an ion conductive polymer. DMA suggests that PC is miscible with PEEA and selectively goes into PEEA phase in case of ternary blends of PTT/PEEA/PC. The glass transition temperature (T_g) for PC/PEEA is well predicted by Gordon Taylor equation. Addition of PC retards the electrostatic decay performance of PTT/PEEA blends by restricting the motion of ions in PEEA through increasing the T_g of PEEA. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Copolymers of poly(arylene sulfide sulfone)/poly(ether sulfone): Synthesis,structure, and rheology properties

In order to overcome the poor flowability of poly(arylene sulfide sulfone) (PASS), we introduced ether bonds into the polymer main chain. A series poly(arylene ether sulfide sulfone) copolymers (PAESS) containing different proportion of ether bonds were synthesized with 4,4′‐dichlorodiphenyl sulfone (DCDPS), sodium sulfide (Na₂S·xH₂O), and 4,4′‐dihydroxydiphenyl ether (DHDPE). The copolymers were characterized by Fourier transform infrared (FTIR), ¹H‐nuclear magnetic resonance (NMR), differential scanning calorimetry, dynamic mechanical analysis (DMA), and rheometer. The results of FTIR and ¹H‐NMR indicate the copolymers are synthesized successfully. PAESS were found to have excellent thermal properties with glass transition temperature (T_g) of 175.7–219.1 °C and 5% weight lost temperature were all above 420 °C. The tensile and DMA test indicates that these resultant copolymers have good mechanical properties with tensile strength of 60 MPa and storage modulus of 1.5 GPa. From the results of rheology properties testing, we found that the melt stability and melt flowability of PASS were improved distinctly from 25,470 Pa s down to 355 Pa s with the incorporation of ether bonds. That will be quite beneficial to the processing of PASS, especially for the thermoforming of precision products. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46534.     

Thermal properties and non‐isothermal crystallization behavior of poly(trimethylene terephthalate)/poly(lactic acid) blends

Thermal properties and non‐isothermal melt‐crystallization behavior of poly(trimethylene terephthalate) (PTT)/poly(lactic acid) (PLA) blends were investigated using differential scanning calorimetry and thermogravimetric analysis. The blends exhibit single and composition‐dependent glass transition temperature, cold crystallization temperature (T_cc) and melt crystallization peak temperature (T_mc) over the entire composition range, implying miscibility between the PLA and PTT components. The T_cc values of PTT/PLA blends increase, while the T_mc values decrease with increasing PLA content, suggesting that the cold crystallization and melt crystallization of PTT are retarded by the addition of PLA. The modified Avrami model is satisfactory in describing the non‐isothermal melt crystallization of the blends, whereas the Ozawa method is not applicable to the blends. The estimated Avrami exponent of the PTT/PLA blends ranges from 3.25 to 4.11, implying that the non‐isothermal crystallization follows a spherulitic‐like crystal growth combined with a complicated growth form. The PTT/PLA blends generally exhibit inferior crystallization rate and superior activation energy compared to pure PTT at the same cooling rate. The greater the PLA content in the PTT/PLA blends, the lower the crystallization rate and the higher the activation energy. Moreover, the introduction of PTT into PLA leads to an increase in the thermal stability behavior of the resulting PTT/PLA blends. Copyright © 2011 Society of Chemical Industry     

Blends of poly[3,3-bis(chloromethyl)oxetane] with poly(vinyl acetate). I. Thermal and mechanical properties

Blends of poly[3,3-bis(chloromethyl)oxetane] (Penton) with poly(vinyl acetate) were prepared. Compatibility, morphology, thermal behavior, and mechanical properties of blends with various compositions were studied using differential scanning calorimetry (DSC), dynamic mechanical measurements (DMA), tensile tests, and scanning electron microscopy (SEM). DMA study showed that the blends have two glass transition temperatures (T_g). The T_g of the PVAc rich phase shifts significantly to lower temperatures with increasing Penton content, suggesting that a considerable amount of Penton dissolves in the PVAc rich phase, but that the Penton rich phase contains little PVAc. The Penton/PVAc blends are partially compatible. DSC results suggest that PVAc can act as a β-nucleator for Penton in the blend. Marked negative deviations from simple additivity were observed for the tensile strength at break over the entire composition range. The Young's modulus curve appeared to be S-shaped, implying that the blends are heterogeneous and have a two-phase structure. This was confirmed by SEM observations. © 1992 John Wiley & Sons, Inc.     

Effects of l‐aspartic acid and poly(butylene succinate) on thermal stability and mechanical properties of poly(propylene carbonate)

Poly(propylene carbonate) (PPC) was modified by l ‐aspartic acid (Asp) and poly(butylene succinate) (PBS). To assess the effects of Asp and PBS on the thermal stability, mechanical properties of PPC, different PPC/Asp, PPC/PBS, and PPC/PBS/Asp blends were prepared by twin‐screw extruder. The results indicated that the thermal stability improved with the Asp content increasing from 0.5 to 5%. With trace presence of 2% Asp, the degradation temperature of PPC was greatly increased upon extruding and the Yield strength and Young's modulus increased 62 and 849 times, respectively, at 20°C. The flexibility of PPC was effectively improved by blending with PBS, the PBS has no significant effect on the thermal stability of PPC until PBS up to enough amount. Besides the Asp additive in PPC/PBS blends not only improved the thermal stability PPC, but improved the interfacial compatibility of the blend. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42970.     

Ionomeric blends of poly(ethylene oxide) with poly(styrene‐co‐maleic anhydride) ionomer: Miscibility,crystallization, and melting behavior

The miscibility and crystallization behavior of poly(ethylene oxide) (PEO) and poly(styrene‐co‐maleic anhydride) ionomer (SMAI) blends were studied by the dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC). This study has demonstrated that the presence of ion–dipole interactions enhances the miscibility of otherwise immiscible polymers in the PEO and high molecular weight poly(styrene‐co‐maleic anhydride) (SMA). The effect of ion–dipole interactions on enhancing miscibility is confirmed by the presence of a single glass transition temperature (T_g) and a depression of the equilibrium melting temperature of the PEO component. The equilibrium melting temperature of PEO in the blends are obtained using Hoffman‐Weeks plots. The interaction energy density, β, is calculated from these data using the Nishi‐Wang equation. The results suggest that PEO and SMAI blends are thermodynamically miscible in the melt. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1–7, 2000     

Compatibilization of the poly(lactic acid)/poly(propylene carbonate) blends through in situ formation of poly(lactic acid)‐b‐poly(propylene carbonate) copolymer

The in situ formation of poly(lactic acid)‐b‐poly(propylene carbonate) (PLA‐b‐PPC) block copolymers were carried out by the reaction between PLA and PPC in the presence of tetrabutyl titanate via transesterification. Molecular weight measurements and ¹³C nuclear magnetic resonance spectroscopy revealed that PLA‐b‐PPC block copolymers with higher molecular weight were obtained by controlling the reactivity point ratio between PLA chains and PPC chains in PLA/PPC reaction system. The sample with a composition of PLA:PPC = 40:60 (wt %) and a catalyst amount of 0.5 wt % had a more proportionable reactivity point ratio between PLA chains and PPC chains compared with other samples, resulting in a most conspicuous transesterification and inconspicuous chain scission reaction. Therefore, its high molecular weight fraction (M_w > 40.0 × 10⁴) increased 80%. The formation of macromolecular PLA‐b‐PPC copolymer could strengthen the entanglement between PLA and PPC molecular chains, which resulted in an increased viscosity of blends at low shear rate. In addition, the elongation at break of sample with a composition of PLA:PPC = 40:60 (wt %) and a catalyst amount of 0.5 wt % was nearly as twice as which without catalyst because of the improving miscibility of PLA domains and PPC matrix by the compatibilization of PLA‐b‐PPC copolymer. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46009.     

PBS/PBAT共混型全生物降解材料的制备及其性能研究

通过熔融共混法制备了聚丁二酸丁二醇酯（PBS）/聚己二酸对苯二甲酸丁二酯（PBAT）共混物,用熔体流动速率法、扫描量热法、X射线衍射、扫描电镜法及力学性能测试等手段研究了PBS/PBAT共混物的熔体流动性、结晶性能、力学性能以及共混物相容性。结果表明,随着PBAT含量的增加,PBS/PBAT共混体系的拉伸强度先升高后降低,断裂伸长率不断提高,冲击强度先降低后提高;当PBAT含量为20 %（质量分数,下同）时,与纯PBS相比,断裂伸长率提高10倍,冲击强度提高82 %,而拉伸强度仅仅降低6 %。     

Radiation‐induced crosslinking and mechanical properties of blends of poly(lactic acid) and poly(butylene terephthalate‐co‐adipate)

Blends of poly(L ‐lactic acid) (PLLA) and poly (butylene terephthalate‐co‐adipate) (PBTA) were prepared at ratios of 50 : 50, 60 : 40, and 80 : 20 by melt blending in a Laboplastomill. Improved mechanical properties were observed in PLLA when it was blended with PBTA, a biodegradable flexible polymer. Irradiation of these blends with an electron beam (EB) in the presence of triallyl isocyanurate (TAIC), a polyfunctional monomer, did not cause any significant improvement in the mechanical properties, although the gel fraction increased with the TAIC level and dose level. Irradiation of the blends without TAIC led to a reduction in the elongation at break (E_b) but did not show a significant effect on the tensile strength. E_b of PBTA was unaffected by EB radiation in the absence of TAIC. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Miscibilities and rheological properties of poly(butylene succinate)–Poly(butylene terephthalate) blends

An aliphatic/aromatic polyester blend has been dealt with in this study. As an aliphatic polyester, poly(butylene succinate) (PBS) was used, which is thought to possess biodegradability, but it is relatively expensive. It has been blended with poly(butylene terephthalate) (PBT) in order to obtain a biodegradable blend with better mechanical properties and lower cost. The miscibilities of PBS–PBT blends were examined not only from the changes of T_g but also from log G′–log G" plots. Dynamic mechanical thermal analyzer (DMTA) was an appropriate, sensitive method to obtain the glass transitions properly. Thermal stabilities of PBS and PBT were also verified at the temperature of 240°C. A transesterification reaction between two polyesters at 240°C was hardly detectable so that it did not affect the miscibilities and properties of the blends. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 945–951, 1999     

Structure and improved properties of PPC/PBAT blends via controlling phase morphology based on melt viscosity

Poly(propylene carbonate) (PPC)/poly(butylenes adipate-co-terephthalate) (PBAT) blends with various composition ratios were prepared via melt mixing using a twin-screw extruder. The effect of melt viscosities of polymers on mechanical behavior, interfacial interaction, thermal properties, rheological responses, and phase morphology was investigated. Results showed that the phase morphology and properties of PPC/PBAT blends were affected by the composition of the blends and the melt viscosities of the two polymers. Results of tensile tests, FTIR, and dynamic rheological measurement of PBAT-rich blends exhibited a better mechanical properties, intermolecular interactions, and compatibility when compared with PPC-rich blends due to the differences of their melt viscosities. Incorporating of PBAT effectively improved the T_g of PPC and the thermal stability of the blends. The T_c of PPC/PBAT blends markedly increased from 37.5 to 66.8 °C with addition of only 10 wt% PPC, indicating an enhanced crystallization ability of PBAT. The improvement of T_c was helpful for blown film extrusion. SEM microphotographs showed that the size of the dispersed phase particles is much smaller and the distribution is more uniform for PBAT-rich blends, compared with that in PPC-rich blends. The processing stability of blown film extrusion was improved by blending PPC with PBAT. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48924.     

Biodegradable poly(ethylene succinate) blends and copolymers containing minor amounts of poly(butylene succinate)

Poly(ethylene succinate) (PES), poly(butylene succinate) (PBS), and PES‐rich copolyesters were synthesized using an effective catalyst, titanium tetraisopropoxide. PES was blended with minor amounts of PBS for the comparison. The compositions of the copolyesters and the blends were determined from NMR spectra. Their thermal properties were studied using a differential scanning calorimeter (DSC), a temperature modulated DSC (TMDSC), and a thermogravimetric analyzer. No significant difference exists among the thermal stabilities of these polyesters and blends. For the blends, the reversible curves of TMDSC showed a distinct glass‐rubber transition temperature (T_g), however, the variation of the T_g values with the blend compositions was small. Isothermal crystallization kinetics and the melting behavior after crystallization were examined using DSC. Wide‐angle X‐ray diffractograms (WAXD) were obtained for the isothermally crystallized specimens. The results of DSC and WAXD indicate that the blends have a higher degree of crystallinity and a higher melting temperature than those of the corresponding copolymers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effects of molecular weight on phase structure of poly(ethylene terephthalate)/poly(ethylene 2,6‐naphthalate) blends

The phase structure of poly(ethylene terephthalate)/poly(ethylene 2,6‐naphthalate) (PET/PEN) blends was studied in relation to the molecular weight. The samples were prepared by both solution blends, which showed two glass‐transition temperatures (T_g), and melt blends (MQ), which showed a single T_g, depending on the composition of the blends. The T_g of the MQ series was independent of the molecular weight of the homopolymer, although the degree of transesterification in the blends was affected by the molecular weight. The MQ series showed two exotherms during the heating process of a differential scanning calorimetry scan. The peak temperature and the heat flow of the exotherms were affected by the molecular weight of the homopolymers. The strain‐induced crystallization of the MQ series suggested the independent crystallization of PET and PEN. Based on the results, a microdomain structure of each homopolymer was suggested. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2428–2438, 2005     

Crystallization behavior of partially crosslinked poly(β‐hydroxyalkonates)/poly(butylene succinate) blends

Partially crosslinked poly(β‐hydroxybutyrate‐co‐β‐hydroxyvalerate)/poly(butylene succinate) (PHBV/PBS) and poly(β‐hydroxybutyrate)/poly(butylene succinate) (PHB/PBS) blends were prepared by melt compounding with dicumyl peroxide. The effect of partial crosslinking on crystallization of the PHBV/PBS and PHB/PBS blends was investigated systematically. Differential scanning calorimetry results showed that the overall crystallization rates of both PHBV and PBS in their blends were enhanced considerably by the partial crosslinking. Similar results were also detected in the PHB/PBS blends. The polarized optical microscope observation displayed that the nuclei density of PHBV was increased while the spherulitic morphology did not change much. Conversely, the PBS spherulites turned into cloud‐like morphology after the partial crosslinking which is a result of the decrease in spherulite size, the reduction in interspherulite distance and the interconnection of fine PBS domains. Wide angle X‐ray diffraction patterns confirmed the enhancement in crystallization of the PHBV/PBS blends after the partial crosslinking without modification on crystalline forms of the PHBV and PBS components. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41020.     

Biobased blends of poly(propylene carbonate) and poly(hydroxybutyrate‐co‐hydroxyvalerate): Fabrication and characterization

Poly(propylene carbonate) (PPC), a CO₂‐based bioplastic and poly(hydroxybutyrate‐co‐hydroxyvalerate) (PHBV) were melt blended followed by injection molding. Fourier transform infrared spectroscopy detected an interaction between the macromolecules from the reduction in the OH peak and a shift in the C?O peak. The onset degradation temperature of the polymer blends was improved by 5% and 19% in comparison to PHBV and PPC, respectively. Blending PPC with PHBV reduced the melting and crystallization temperatures and crystallinity of the latter as observed through differential scanning calorimetry. The amorphous nature of PPC affected the thermal properties of PHBV by hindering the spherulitic growth and diluting the crystalline region. Scanning electron micrographs presented a uniform dispersion and morphology of the blends, which lead to balanced mechanical properties. Incorporating PHBV, a stiff semi‐crystalline polymer improved the dimensional stability of PPC by restricting the motion of its polymer chains. © 2016 The Authors Journal of Applied Polymer Science Published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44420.