Heat Distortion Temperature Research Articles

3D Printing of sustainable coal polymer composites: Thermophysical characteristics

Recently, there has been a growing interest in enlisting polymer-based additive manufacturing in high-volume structural applications such as wind turbine blade tooling and additive housing construction. However, the availability of sustainable and environmentally friendly 3D printable materials could present a serious challenge, precluding the technology expansion to such applications. This research was focused on developing sustainable and environmentally friendly coal-plastic composites for use in high-volume applications. Polylactic acid, polyethylene terephthalate glycol, high-density polyethylene, and polyamide-12 resins were melt-mixed with bituminous Pittsburgh No. 8 coal at loadings varying from 20 wt % to 70 wt % coal. Thermoplastic composite filaments were extruded and processed with commercial 3D printers. Important thermophysical properties including coefficients of thermal expansion, heat deflection temperatures, glass transition and melt temperatures, specific heat capacities, thermal conductivities, and thermal stabilities of the coal-plastic composites were investigated. Coefficient of thermal expansion values for the composites had an inverse relationship with coal content lending to decreased print warping and consistent 3D printing of high-density polyethylene materials. Coal increased the heat deflection temperature of high-density polyethylene composites while little to no effect was observed for the other plastics. All composites maintained comparable melt temperatures, allowing for processing with commercial equipment. Specific heat capacity and thermal conductivity decreased with coal loading for all composite materials. Thermogravimetric analysis under air showed that the introduction of coal improved the thermal stability of all plastics by increasing the decomposition temperatures at 5 % and 50 % weight loss and by reducing the maximum decomposition rates.

Tailoring PLA/ABS Blends Compatibilized with SEBS-g-MA through Annealing Heat Treatment.

In this work, blends based on poly (lactic acid) (PLA)/acrylonitrile-butadiene-styrene (ABS) compatibilized with maleic anhydride-grafted (SEBS-g-MA) were prepared in a co-rotational twin-screw extruder by varying the concentrations of the compatibilizing agent. The influence of the compatibilizing agent on the morphology, mechanical, thermal, thermomechanical, and rheological properties of the prepared materials was analyzed. The effect of annealing on the properties of the blends was also investigated using injection-molded samples. The X-ray diffraction (XRD) results proved that the increments in crystallinity were an effect of annealing in the PLA/ABS/SEBS-g-MA blends, resonating at higher heat deflection temperatures (HDTs). The impact strength of the PLA/ABS blends compatibilized with 10 wt% SEBS-g-MA was significantly increased when compared to the PLA/ABS blends. However, the hardness and elastic modulus of the blends decreased when compared to neat PLA. The refined morphology shown in the scanning electron microscopy (SEM) analyses corroborated the improved impact strength promoted by SEBS-g-MA. The torque rheometer degradation study also supported the increased compatibility between SEBS-g-MA, PLA, and ABS. The TGA results show that the PLA/ABS and PLA/ABS/SEBS-g-MA blends are more thermally stable than the neat PLA polymer at higher temperatures. The results showed that the ideal composition is the heat-treated PLA/ABS/SEBS-g-MA (60/30/10 wt%), given the high impact strength and HDT results. The results of this work in terms of mechanical improvement with the use of compatibilizers and annealing suggest that the PLA/ABS/SEBS-g-MA system can be used in the production of 3D-printing filaments.

Preparation of a novel bio‐based ferric flame retardant for enhancing flame retardancy, mechanical properties, and heat resistance of polylactic acid

AbstractA fully bio‐based flame retardant PNF was prepared based on phytic acid, nicotinamide and iron salts in aqueous solution by a green and convenient ionic reaction, and then blended with polylactic acid (PLA) to improve its properties. The results demonstrated that the PLA composite containing 4 wt% PNF(PLA/4PNF) had a flame retardancy rating of UL 94 V‐0 and an oxygen index of 25.3%. In addition, the peak heat release rate (PHRR) and total heat release (THR) of PLA/4PNF were reduced by 27.0% and 27.7%, respectively, compared to pure PLA, and the flame retardancy index (FRI) was increased by 210%, demonstrating that PNF could effectively improve the flame retardancy of PLA. Moreover, the thermal conductivity of PLA/4PNF increased by 284% compared to pure PLA, making the material require higher heat to reach the combustion state. DSC and mechanical property tests showed that PLA/4PNF had 31.3% higher crystallinity, 5.2% higher heat deflection temperature and 10.0% higher flexural modulus compared to pure PLA, indicating that PNF effectively improved the mechanical properties and heat resistance of PLA. The research in this article broadens the application of bio‐based flame‐retardant PLA in the field of electronic appliances and office equipment.

Balancing the Strength-Impact Relationship and Other Key Properties in Polypropylene Copolymer-Natural CaSO4 (Anhydrite)-Filled Composites.

To develop novel mineral-filled composites and assess their enhanced properties (stiffness, a good balance between mechanical strength and impact resistance, greater temperature stability), a high-impact polypropylene copolymer (PPc) matrix containing an elastomeric discrete phase was melt mixed with natural CaSO4 β-anhydrite II (AII) produced from gypsum rocks. First, in a prior investigation, the PPc composites filled with AII (without any modification) displayed enhanced stiffness, which is correlated with the relative content of the filler. The tensile and impact strengths dramatically decreased, especially at high filling (40 wt.%). Therefore, two key methods were considered to tune up their properties: (a) the ionomeric modification of PPc composites by reactive extrusion (REx) with zinc diacrylate (ZA), and (b) the melt mixing of PPc with AII surface modified with ethylenebis(stearamide) (EBS), which is a multifunctional processing/dispersant additive. The properties of composites produced with twin-screw extruders (TSEs) were deeply assessed in terms of morphology, mechanical, and thermal performance, including characterizations under dynamic mechanical solicitations at low and high temperatures. Two categories of products with distinct properties are obtained. The ionomeric modification by Rex (evaluated by FTIR) led to composites characterized by remarkable thermal stability, a higher temperature of crystallization, stronger interfacial interactions, and therefore noticeable mechanical properties (high tensile strength (i.e., 28 MPa), increased stiffness, moderate (3.3 kJ/m2) to good (5.0 kJ/m2) impact resistance) as well as advanced heat deflection temperature (HDT). On the other hand, the surface modification of AII with EBS facilitated the dispersion and debonding of microparticles, leading to composites revealing improved ductility (strain at break from 50% to 260%) and enhanced impact properties (4.3-5.3 kJ/m2), even at high filling. Characterized by notable mechanical and thermal performances, high whiteness, and a good processing ability, these new PPc-AII composites may be tailored to meet the requirements of end-use applications, ranging from packaging to automotive components.

Machine learning-based heat deflection temperature prediction and effect analysis in polypropylene composites using catboost and shapley additive explanations

Among the various physical properties of polypropylene composites (PPCs), heat deflection temperature (HDT) during PPC production is significant because it is directly related to the mechanical behavior of such products. However, it is difficult to predict and analyze the HDT of PPCs owing to the absence of a mathematical or theoretical model. Moreover, categorical data which has different physical properties despite using same substances made predictions highly difficult in PPCs. Here, this study proposed an indicator to analyze the categorical data and Catboost-based model for HDT prediction considering the categorical data. First, the categorization and minimum-based values (MBVs), a dimensionless factor used to calculate HDT differences in the categorical dataset, are applied to detect and split categorical data in a PPC dataset. Second, a case study was conducted on the dataset using three algorithms to compare the proposed model with other traditional machine-learning approaches. As a result, the proposed model provides the highest prediction performance of R2=0.8965 and 0.9801, for the total test dataset and the categorical dataset, respectively. In addition, the effect analysis of substances on HDT was conducted to get some prospective substances for the required HDT using Shapley Additive Explanations (SHAP). Thus, the results of this study can provide a guidance for selecting prospective substances using SHAP result for the target HDT and adjusting the substance ratio using the proposed model. It is expected that this framework has the potential for being applied to the other blending processes to produce products with the required properties.

Calibration of Heat Distortion and Vicat Softening Temperature Apparatus

Heat distortion and Vicat softening temperature apparatus are mainly used for measuring the thermal deformation temperature and Vicat softening point temperature of non-metallic materials. Parameters such as temperature indication error, heating rate error, deformation indication error, and mass indication error of loaded weights can directly decide the quality of heat distortion and Vicat softening temperature apparatus. There is no relevant calibration specification or method for heat distortion and Vicat softening temperature apparatus in China. This article presents a novel calibration method by determining corresponding environmental conditions, calibration standards, and calculation equations. The calibration results show that the method is scientific and practical for metrological performance evaluation of heat distortion and Vicat softening temperature apparatus.

Development of Environmentally Ecofriendly Composites Based on Polypropylene/Bahia Beige Waste: Effect of Reinforcement Content on Physical, Mechanical, Chemical, and Microstructural Properties

This article presents the development and characterization of environmentally friendly composites comprising polypropylene (PP) reinforced with Bahia Beige (BB) marble waste. The composites were prepared using different PP/BB weight ratios and analyzed for their chemical, physical, mechanical, microstructural, and thermal properties. X-ray fluorescence (XRF) analysis revealed the composition of BB, which exhibited a significant concentration of CaO, indicating the presence of calcite and other oxides. X-ray diffraction (XRD) analysis confirmed the presence of PP and identified calcite, dolomite, and quartz phases in the composites. Due to enhanced ceramic reinforcement, the composites displayed increased crystallinity with higher BB content. Fourier-transform infrared (FTIR) analysis demonstrated the interaction between PP and BB, with the bands corresponding to PP being replaced by bands related to BB as filler content increased. The density tests indicated a slight increase in composite density without deviating significantly from pure PP, which is advantageous for low-density applications. The hardness of the composites increased with filler content, while the impact resistance decreased notably. Scanning electron microscopy (SEM) images showed the good distribution of BB within the composites and the presence of ductile characteristics on the composite surface. The heat deflection temperature (HDT) results revealed that adding BB up to 40% by weight increased HDT, whereas a significant reduction occurred at a 50% BB content. These composites demonstrated favorable properties for engineering applications, offering a sustainable solution through utilizing natural waste resources and contributing to Brazilian sustainability efforts.

Tailoring polyamide 6 to exhibit super‐tough behavior and high thermomechanical stability: The role of AES and EPDM‐MA hybridization

AbstractHigh‐performance blends based on polyamide 6 (PA6) were prepared using a hybrid mixture of acrylonitrile/EPDM/styrene (AES) and maleic anhydride grafted ethylene–propylene–diene (EPDM‐MA). Samples were processed in a twin‐screw extruder and injection molded. The torque curves of the PA6/AES/EPDM‐MA blends shifted to higher torque values with added EPDM‐MA, suggesting a chemical interaction between the components. The melt flow index (MFI) results for the PA6/AES/EPDM‐MA blends confirmed the intensification of the flow resistance. Intense infrared absorption peaks for NH and CO indicated that the amine groups of PA6 reacted with the maleic anhydride in EPDM‐MA. The 60/25/15 wt% PA6/AES/EPDM‐MA blend showed an impact strength over 800 J/m, heat deflection temperature (HDT) of 62.3°C, elongation at break of 115%, and contact angle of 59.1°, corresponding to increases of 1718%, 10.5%, 297%, and 10%, respectively, compared to neat PA6. When examined by scanning electron microscopy, the morphology showed a fracture surface with a high degree of plastic deformation and the formation of elastic microfibrils, contributing to the super toughening of the PA6/AES/EPDM‐MA (15%) system. These results indicate the technological potential of the PA6/AES/EPDM‐MA (15 wt%) blends for application in industrial sectors that require super‐tough plastics.

Enhanced mechanical properties, thermal behavior and foaming ability of PP‐g‐MAH modified PP/BF composites

AbstractThe mechanical properties of fiber‐reinforced polymer composites strongly depend on its interfacial bond strength and fiber content, and their further lightweight is the current urgent demands for industry. Basalt fiber (BF), as an emerging natural and environmental‐friendly material, possess a broad application prospect as it can replace glass fiber. Herein, strong PP/BF composites with excellent heat deflection temperature and enhanced impact performance were successfully prepared, which augmented with the increase of BF content. The effect of PP grafted with maleic anhydride (PP‐g‐MAH) on the interfacial bonding properties between BF and PP was investigated based on the PP/20BF composite system, which was significantly improved due to the reaction of maleic anhydride polar groups with the hydroxyl groups on the BF surface. The incorporation of PP‐g‐MAH led to 24.7%, 46.9%, and 77.2% increase in tensile strength, flexural strength and impact strength of PP/20BF composites, respectively. Moreover, the crystallization properties, rheological behavior and thermal stability of the composites were significantly enhanced, which all contributed to the refinement and densification of cellular structure. The cell size was reduced from 36.38 to 13.41 μm after the addition of PP‐g‐MAH with an opening distance of 2 mm, and the cell density was enhanced by nearly one order of magnitude to 6.43 × 107 cells/cm3. The cellular structure further lightens the weight of product and promotes the lightweight development of PP/BF composites.

Study on the Mechanical Characteristics, Heat Resistance, and Corrosion Resistance of Unsaturated Polyester Resin Composite

In this study, the researchers aimed to broaden the applications of unsaturated polyester resin (UPR) composites in the building field by incorporating surface-modified titanium dioxide (TiO2) nanoparticles and reinforced chopped glass fibers within the UPR matrix. Specifically, the composites containing 4 wt.% TiO2 nanoparticles and 30 wt.% chopped glass fiber exhibited remarkable properties of 46.1 kJ/m2 in impact strength, 90.1 MPa in flexural strength, 78.8 MPa in tensile strength, and 121.5 °C in heat deflection temperature, which improve 207.5%, 80.3%, 62.5%, and 73.6%, respectively, when compared with the blank sample. Furthermore, the results of the corrosion resistance test showed that the composites performed poorly against polar organic and alkaline solutions, presented good corrosion resistance against acidic media, and behaved relatively stable in the salt solution.

Extraction of natural fibers of Catole coconut (Syagrus Cearensis): Application as reinforcing filler in polypropylene‐based composites

AbstractPolypropylene/Syagrus Cearensis fiber composites compatibilized with polypropylene‐graft‐maleic anhydride (PP‐g‐MA) and styrene(ethylene‐butylene)‐styrene copolymer (SEBS‐g‐MA) were successfully produced using a co‐rotating twin‐screw extruder followed by injection molding. The composites were characterized by X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The mechanical properties were determined by Izod impact and tensile testing. Thermal properties were obtained by thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). Heat deflection temperature (HDT) was determined to study the thermomechanical properties of the composites. XRD and DSC indicated the presence of two polypropylene polymorphs: α and β. The unmodified PP/Fiber composites showed an incompatible behavior, presenting low fiber/matrix interaction and poor interfacial adhesion. The poor compatibility led to low elongation at break and impact strength but high tensile strength. PP‐g‐MA coupling agent promoted some adhesion to the PP/fiber interfaces but not enough to improve the impact strength. The composites with PP‐g‐MA exhibited improved tensile modulus and strength. The enhanced PP/fiber interfacial interaction promoted by SEBS‐g‐MA generated a better interplay of mechanical properties, improving impact strength and elongation at break while preserving the elastic modulus and tensile strength. In general, the fibers enhanced the thermomechanical stability of PP, as evidenced by higher HDT values.

Additive Manufacturing Post-Processing Treatments, a Review with Emphasis on Mechanical Characteristics.

Additive manufacturing (AM) comes in various types of technologies and comparing it with traditional fabrication methods provides the possibility of producing complex geometric parts directly from Computer-Aided Designs (CAD). Despite answering challenges such as poor workability and the need for tooling, the anisotropy of AM constructions is the most serious issue encountered by their application in industry. In order to enhance the microstructure and functional behavior of additively fabricated samples, post-processing treatments have gained extensive attention. The aim of this research is to provide critical, comprehensive, and objective methods, parameters and results' synthesis for post-processing treatments applied to AM builds obtained by 3D printing technologies. Different conditions for post-processing treatments adapted to AM processes were explored in this review, and demonstrated efficiency and quality enhancement of parts. Therefore, the collected results show that mechanical characteristics (stress state, bending stress, impact strength, hardness, fatigue) have undergone significant improvements for 3D composite polymers, copper-enhanced and aluminum-enhanced polymers, shape memory alloys, high-entropy alloys, and stainless steels. However, for obtaining a better mechanical performance, the research papers analyzed revealed the crucial role of related physical characteristics: crystallinity, viscosity, processability, dynamic stability, reactivity, heat deflection temperature, and microstructural structure.

Achieving anti‐moisture absorption and high thermal properties in bio‐based polyamide 56/F‐based heat‐resistant agent composites through crystal regulation

AbstractThe anti‐moisture absorption and thermal properties of bio‐based polyamide 56 (PA56) were improved by adding heat‐resistant agents to expand its application in the automotive field. Two macromolecular heat‐resistant agents, p(N‐(4‐F‐phenylmaleimide)‐alt‐styrene) (PFS) and p(N‐(4‐F‐phenylmaleimide)‐alt‐triallyl isocyanurate) (PFT), were synthesized via precipitation polymerization, and their effects on the thermal properties, mechanical properties, and anti‐moisture absorption of PA56 were studied. Compared with PA56, the heat deflection temperature of PA56/PFS and PA56/PFT composites was improved by 11.9% and 21.2%, with their anti‐moisture absorption increasing by 14.6% and 15.5%, respectively. This is due to the crystallization of PA56 has been promoted and its more complete crystal structure has been obtained.

Toward Reactive Processing of Polyamide 6 Based Blends with Polyethylene Grafted with Maleic Anhydride and Acrylic Acid: Effect of Functionalization Degree

AbstractThe reactivity of different polyethylene modifiers based on acrylic acid (AA) and maleic anhydride (MA) with polyamide 6 (PA6) is investigated, using several degrees of functionalization. The polymer blends are processed in an internal mixer and injection molded. Mechanical, rheological, infrared spectroscopy, thermal, thermomechanical properties, and morphology are evaluated. The torque rheometry results show that higher functionalization degrees favored a high reactivity with PA6. As a consequence, there is an increase in the viscosity of the polymer blends, which is reflected in the reduction of the melt flow index (MFI), compared to PA6. High impact strength and elongation at break properties confirm the blends' compatibility. The elastic modulus and the tensile strength maintain high values, suggesting a balance of mechanical properties. In addition, the polymer blends' heat deflection temperature (HDT) and thermal stability properties are comparable to neat PA6. The morphology obtained by scanning electron microscopy show dispersed and refined particles in the PA6 matrix, indicating stabilization at the interface. Incorporating only 10% of high‐density polyethylene grafted with acrylic‐acid (HDPE‐g‐AA) is very efficient in optimizing the properties of PA6, contributing to broadening the range of applications for the processing industry.

A sustainable approach for developing biocarbon from lignin and its utilization in recycled ocean nylon based biocomposites

Nylon/polyamide (PA6) is a major cause of ocean plastic pollution because of its extended use in commercial fishing activities. Recovery of this nylon from oceans and its use in manufacturing new materials or composites is urgently required to promote sustainability and circularity. In this work, unlike higher-density mineral fillers, lignin from the forestry industry was converted into biocarbon, which was used as a lightweight filler to manufacture recycled-ocean nylon (RN)-based composites. Biocarbon is a highly stable, competitive, and sustainable filler for high-performance engineering plastics such as nylon. Lignin was pyrolyzed at 600 °C followed by further treatment at 1200 °C (with and without cobalt (II) nitrate catalyst) to induce graphitization in the produced biocarbon. Among the three types of biocarbon samples, such as pyrolyzed at 600 °C, 1200 °C and 1200 °C catalyzed lignin biocarbon, the catalyzed biocarbon showed the maximum electrical conductivity. Catalyzed lignin biocarbon pyrolyzed at 1200 °C showed an increase of 85% in electrical conductivity compared to commercial mineral graphite. The biocomposites consisting of 600 °C biocarbon were manufactured by injection molding at different filler contents up to 40 wt.%. The biocomposites consisting of 40% of pyrolyzed lignin at 600 °C showed increased flexural strength, flexural modulus, and heat deflection temperature by 41, 76 and 76%, respectively, compared to neat RN. Improved properties of the prepared biocarbons and biocomposites showed the potential of RN-based composites in the automotive industries.

Thermal and morphological properties of polyhydroxyalkanoate/ nanosilver composite

Conventional plastic can lead to endless pollution as it took millions of years to be disposed of, hence an alternative to using biodegradable plastic replacing regular everyday plastic has highly participated. Polyhydroxyalkanoates (PHA) have the characteristics of a biodegradable plastic however, it exhibits low heat distortion temperature. The objective of this research is to investigate the effect of nanosilver additions on the thermal properties of the PHA composite and its morphology behavior. Initially,4 wt/v of PHA was dissolved into 30mL dichloromethane at room temperature. After that, the nanosilver particle was added with 10mL dichloromethane and it was ultrasonicated at 10 minutes. Ultrasonicated nanosilver in dichloromethane mixture was mixed with PHA in dichloromethane for 20 minutes using a magnetic stirrer. Then, thin polymeric films with a thickness of 10 µm were obtained by the solution casting method. The obtained films were then carefully dried at room temperature for 24 hours. These steps were repeated with the addition of 0.25 wt% and 0.5wt% nanosilver suspension in dichloromethane to PHA solution. The thermal properties and morphology analysis of PHA/nanosilver composite will be investigated using thermal gravimetric analysis(TGA) and field emission scanning electron microscopy (FESEM). Based on thermal properties, PHA/0.5wt% nanosilver has shown a lower onset temperature compared to the pure PHA. This indicates that PHA/0.5wt% nanosilver has a slower degradation rate and higher thermal stability. In conclusion, nanosilver has greatly improved PHA properties into promising biodegradable plastics.

Carbon Nanotube-, Boron Nitride-, and Graphite-Filled Polyketone Composites for Thermal Energy Management.

In order to improve the thermal conductivity of 30 wt % synthetic graphite (SG)-filled polyketones (POKs), conductive fillers such as multiwall carbon nanotubes (CNTs) and hexagonal boron nitride (BN) were used in this study. Individual and synergistic effects of CNTs and BN on 30 wt % synthetic graphite-filled POK on thermal conductivity were investigated. 1, 2, and 3 wt % CNT loading enhanced the in-plane and through-plane thermal conductivities of POK-30SG by 42, 82, and 124% and 42, 94, and 273%, respectively. 1, 2, and 3 wt % BN loadings enhanced the in-plane thermal conductivity of POK-30SG by 25, 69, and 107% and through-plane thermal conductivity of POK-30SG by 92, 135, and 325%. It was observed that while CNT shows more efficient in-plane thermal conductivity than BN, BN shows more efficient through-plane thermal conductivity. The electrical conductivity value of POK-30SG-1.5BN-1.5CNT was obtained to be 1.0 × 10-5 S/cm, the value of which is higher than that of POK-30SG-1CNT and lower than that of POK-30SG-2CNT. While BN loading led to a higher heat deflection temperature (HDT) than CNT loading, the hybrid fillers of BNT and CNT led to the highest HDT value. Moreover, BN loading led to higher flexural strength and Izod-notched impact strength values than CNT loading.

Effect of injection molding conditions on the properties of polyamide 6/calcium carbonate nanocomposite

AbstractThe application range of polyamide 6 in lightweight part applications can be significantly increased by using appropriate processing parameters and by incorporating additives. Therefore, specimens were manufactured at varying mold temperatures and injection velocities to study the effect of injection molding parameters on the properties of polyamide 6 and its nanocomposite with nano‐calcium carbonate. Mechanical properties, degree of crystallinity, density, heat deflection temperature, and melt flow index were measured to assess the effect of injection molding conditions on material properties. Mold temperature was the process factor that most affected polyamide 6 and polyamide 6/nano‐calcium carbonate properties. Increasing this parameter increased density, impact strength, flexural strength, flexural modulus, and heat deflection temperature. The nanocomposite's degree of crystallinity, tensile modulus, and melt flow index also increased. High injection velocity reduced only the impact strength of the nanocomposite. The findings indicate that by modifying injection parameters, it is possible to improve mechanical properties and processing efficiency of polyamide 6 and its nanocomposites, bringing them closer to their maximum potential. Incorporating the nanofiller increased almost all properties except for impact strength and elongation at break. Nano‐calcium carbonate provided considerable advantages to polyamide 6 mechanical performance and processability while increasing sample weight by only 1.5%.

Super-Tough PLA-Based Blends with Excellent Stiffness and Greatly Improved Thermal Resistance via Interphase Engineering.

Super-tough poly(lactic acid)/polycarbonate (PLA/PC) (50/50) blends with an excellent balance of stiffness, toughness, and thermal stability were systematically designed and characterized. Poly(methyl methacrylate) (PMMA) was utilized as a novel, highly effective nonreactive interphase to promote PLA-PC phase compatibility. Partial miscibility of PMMA with both PLA and PC produced strong molecular entanglements across the PLA-PC phase boundary followed by an excellent phase adhesion. This was predicted from interfacial energy measurements and supported by dynamic mechanical thermal analysis, morphological observations, and mechanical tests. Ternary PLA/PC/PMMA blends exhibited an exceptional set of stiffness, tensile and flexural strength, tensile and flexural ductility, and thermal stability together with improved impact strength compared with neat PLA and uncompatibilized PLA/PC blends. Addition of nonreactive polybutadiene-g-styrene-co-acrylonitrile (PB-g-SAN) impact modifier to the compatibilized blend resulted in further dramatic improvements in the dispersion state of PC and PMMA phase domains followed by the development of an interconnected structure of PC, PMMA, and PB-g-SAN domains in the PLA matrix. Such a network-like morphology, with rubbery particles percolated at the interface between the dispersed structures and surrounding PLA matrix, produced a tremendous increase in impact resistance (≈700 J/m) and tensile ductility (≈200% strain) while maintaining excellent stiffness (≥2.1 GPa). The combined effects of interfacial localization of impact modifier particles, network-like morphology (extended over the entire volume of the blend), and strong phase interactions between the components (due to mutual miscibility) are described to be responsible for super-tough behavior. The role of PMMA as an efficient interphase adhesion promoter in the toughened quaternary blends is also clarified. Impact fractography revealed multiple void formations, plastic growth of microvoids, and the formation of void-fibrillar structures around as well as inside the dispersed structures as the main micromechanical deformation processes responsible for massive shear yielding and plastic deformation of blends. Blends designed in this work offer remarkable improvements in tensile and flexural ductility, impact resistance, and heat deflection temperature compared with neat PLA resin. The overall characteristics of these blend systems are comparable and/or superior to those of several commercial thermoplastic resins.

High Content of Thermoplastic Starch, Poly(butylenes adipate-co-terephthalate) and Poly(butylene succinate) Ternary Blends with a Good Balance in Strength and Toughness.

The ternary blends of a high content of thermoplastic starch (TPS), poly(butylenes adipate-co-terephthalate) (PBAT), and poly(butylene succinate) (PBS) were first melt-compounded in a twin screw extruder. The TPS contents in ternary blends were fixed at 60 wt%. The miscibility, morphology, thermal behavior, mechanical properties, and thermal resistance of the blends were investigated. The results showed that dispersions of PBS and PBAT minor phases improved the tensile strength and elongation at break. TPS/PBS/PBAT60/10/30 formed a good balance in strength and toughness. Dynamic mechanical analysis of the blends exhibits an intermediate and peak suggesting the ternary blend is compatible. Minor phase-separated structure SEM results showed that TPS/PBS/PBAT60/10/30 blend formed a typical mixture with core-shell morphology. As the PBAT composition was increased, phase morphology changes occurred in the blends, leading to decreased values of complex viscosity, storage modulus, and loss modulus. Moreover, the thermal resistances and melt flow properties of the materials were also studied by analysis of the heat deflection temperature (HDT) and melt flow index (MFI) value in the work.