Effect Of Blend Composition Research Articles

4D Printing of novel poly(ethylene-vinyl acetate) / poly(butyl methacrylate-co-isobutyl methacrylate) shape memory polymer blends

4D printing is a technology that combines additive manufacturing with shape memory polymers, aiming to enhance the functionality of 3D printed structures. Filaments made from thermoplastic polymers are commonly used in Fused Deposition Modeling (FDM), which is one of the most prevalent types of 3D printing. Here, novel heat-responsive shape memory polymer blends were produced from ethylene-vinyl acetate copolymer (EVA) and poly(butyl methacrylate-co-isobutyl metacrylate) polymers. The effect of blend composition on the morphological, thermal, mechanical, and shape memory properties was investigated. The blend (60E-40B) containing 60 % by weight EVA and 40 % by weight BMA-co-iBMA exhibited optimum shape memory performance with a shape fixing (Rf) of 94.1 % and a shape recovery (Rr) of 94.5 % at a shape transition temperature (Ttrans) of 55 °C. Filament for the 60E-40B blend was produced for FDM type 3D printers, and 4D parts for various applications were printed using this filament. These 4D printed parts, designed for robotic grippers, self-assemble rivets, movable cog-wheel teeth, surface traps, and finger splints, displayed shape recovery characteristics in both hot oven and hot water environments.

Acrylonitrile Butadiene Styrene/Thermoplastic Polyurethane Blends for Material Extrusion Three-Dimensional Printing: Effects of Blend Composition on Printability and Properties.

Blend filaments of acrylonitrile butadiene styrene (ABS) and thermoplastic polyurethane (TPU) were prepared at different weight ratios, i.e., 100:0, 70:30, 50:50, 30:70, and 0:100, for FDM printing; the prepared filaments, with an average diameter of 2.77 ± 0.19 mm, were encoded as A100, A70T30, A50T50, A30T70, and T100, respectively. The properties and printability of the filaments were thoroughly investigated. The blend composition, as well as the printing parameters, were optimized to obtain the FDM-printed objects with a well-defined surface structure and minimized warpages. The glass transition temperatures of ABS and TPU in the blends were not much altered from those of the parent filaments, whereas the thermal degradation characteristics of the blend filaments still fell between those of the neat filaments. The fractured surfaces of the filaments, observed by SEM, appeared smoother when higher amounts of TPU integrated; the smoothest surface of the ABS-based filament was found in A30T70, indicating the well-compatible blend characteristic. This was also confirmed by its rheological behavior examined by a parallel plate rheometer at 225 °C. Not only was the printability of the filaments improved, but also the warpages of the 3D-printed specimens were decreased when increasing amount of TPU was incorporated into the filaments. Among the printed objects, the A30T70 specimen exhibited the evenest surface morphology with the lowest surface roughness value of 32.9 ± 13.2 nm and the most uniform and consistent linear printing structure when being fabricated at the nozzle temperature of 225 °C and the printing bed temperature of 60 °C. However, the incorporation of TPU into the filaments markedly cut down both strength and modulus values of the fabricated materials up to about half but assisted the printed articles to absorb more energy, demonstrating that this polymer served as a good and effective toughener for ABS.

Investigation of shape memory and mechanical properties of styrenic thermoplastic elastomer/PCL blends: Effect of blend composition

Investigation of shape memory and mechanical properties of styrenic thermoplastic elastomer/PCL blends: Effect of blend composition

Biochar from Digestate Pyrolysis as a Filler for Biopolymer Blends: Effect of Blend Composition

Abstract This study investigates the effect of biochar (BC) as a filler for biopolymer blends, with a focus on the effect of the biopolymer weight ratio on the final BC-added blends. The blends studied in this work were obtained by varying the weight ratio of poly-butylene adipate-co-terephthalate (PBAT) and polylactic acid (PLA) due to their great importance in packaging and agricultural fields. BC has been produced in our laboratories by the slow pyrolysis of the digestate obtained from the anaerobic digestion of the organic fraction of municipal solid waste (OFMSW). After pyrolysis, digestate-derived biochar has been milled and sieved to produce a powdery form with diameter of less than 45 μm. In order to better investigate the filler/polymer interactions, biochar particles were dimensionally, morphologically and chemically characterised. The inhomogeneity of the feedstock is responsible for content and high diversity of inorganics in biochar surface. The effect of BC on PBAT and PLA biopolymer matrices is different, and for the blend compositions the relative weight ratio between PBAT and PLA plays an important role. Furthermore, the biocomposite blend has been fully characterised: rheological, morphological, mechanical and dynamic-mechanical characterisations have been carried out, highlighting how the properties results strongly influenced by the presence of BC in the blend. In addition, a study of the viscous molar mass of the two polymer matrices when processed in the presence or absence of BC particless highlighting that a strong chemical interaction occurs between PLA and BC particles, unlike PBAT and BC. Graphical Abstract

4D printable maleated poly(styrene-b-ethylene/butylene-b-styrene) / Poly(ethylene-co-vinyl acetate) thermoplastic elastomer blends; effects of blend composition on shape memory and mechanical properties

Shape memory polymers are attracting attention in materials science with their responsive properties and their application areas are gradually developing. By adapting these materials to the additive manufacturing process, four-dimensional (4D) printing technology has been developed. In this study, novel thermo-responsive shape memory polymer blends were prepared for high temperature applications from commercially available polymers using maleated poly(styrene-b-ethylene/butylene-b-styrene) (SEBS-g-MA) and poly(ethylene-co-vinyl acetate) (EVA) and their applicability in three-dimensional (3D) printing was explored. The presence of SEBS-g-MA led to an increase in the degree of crystallization and glass transition temperature of EVA, accompanied by a decrease in crystallization temperature. As the EVA content increased, the blend morphology transitioned from droplet to co-continuous structure. Higher EVA content resulted in an increase in Young's modulus, but a decrease in tensile strength. Nevertheless, these blends exhibited exceptional elongation at break, surpassing 1200%. The blend comprising 70 wt% SEBS-g-MA and 30 wt% EVA demonstrated a synergistic effect, yielding the highest values for elastic modulus, creep resistance, and storage modulus. Furthermore, the blend with 60 wt% SEBS-g-MA and 40 wt% EVA exhibited optimal shape memory performance, achieving a shape fixing ratio of 93.1% and a shape recovery ratio of 98.7%. The conducted analyses demonstrated that the shape recovery of the produced blends could be adjusted according to temperature, and the blends were able to consistently replicate the shape memory effect across multiple cycles. A filament was manufactured for a 3D printer from the blend of 60 wt% SEBS-g-MA and 40 wt% EVA. Using this filament, 4D models having complex geometries were successfully printed. The produced models were able to maintain their temporary shapes to a significant degree. When triggered by heat, these models rapidly returned to their original shapes within a very short period.

A novel organic solvent-free method for manufacturing polyethersulfone hollow fiber membranes using melt extrusion

Hollow fiber membranes are traditionally manufactured using the spinning process, which takes advantage of the phase separation/inversion for the creation of a porous structure. In this work, the use of melt extrusion led to the fabrication of hollow fiber membranes without the use of organic solvents. Following post-treatment, the fabricated partially dense fibers are transformed into porous fibers. In detail, ternary blends of polyethersulfone/poly(ethylene glycol)/poly(N-vinyl pyrrolidone) (PESU/PEG/PVP) were developed by combining a solvent-free liquid mixture of PEG/PVP into PESU. Using a single screw extruder, this blend was melted and extruded using an annular slit nozzle where PEG functioned as a plasticizer, i.e., decreased processing temperatures, while PVP aided in retaining the hollow fiber geometry. These hollow fibers were comprised of uniformly closed pores, occurring due to the expansion and formation of bubbles of evaporating PEG nucleated by PVP during extrusion. By immersing these fibers into an aqueous solution of sodium hypochlorite (NaOCl), PEG and PVP were removed, which led to an open porous structure with pore sizes between 100 nm and 1 μm throughout the membrane. The outer surfaces of the hollow fibers were found to contain a higher PVP content than the inner surface. As PVP and PESU are miscible, i.e., blended in a single phase, treatment with NaOCl led to the creation of open pores on the outer surface with pore sizes between 10 and 150 nm, thus deeming the outer surface functional as a separation layer. The effect of blend composition, extrusion settings, and post-treatment parameters on membrane morphology, water flux, thermal characteristics, and tensile strength was studied, while after the modification, near-pristine PESU membranes were pursued. A water-flux of 28 L/h m2 bar and a molecular weight cut-off (MWCO) of 90%, 75%, and 40% for poly(ethylene oxide) of an average of 1000 kDa, 400 kDa, and 100 kDa molecular weight, respectively, proved that via extrusion it is possible to produce hollow fiber membranes for ultrafiltration without the use of organic solvents.

New insights on the effects of blend composition on the biodegradation and permeability of Inulin-Eudragit RS film coatings for colon drug delivery

Inulin has been applied in Inulin-Eudragit RS (Inu-ERS) coatings as the component responsible for degradation by human microbiota. However, studies on how bacterial enzymes can degrade polysaccharides like inulin imbedded in water insoluble polymers like Eudragit RS are still elusive. The present work aims at elucidating the complex process of enzyme triggered biodegradation of inulin with various molecular weights in isolated films with Eudragit RS. The ratio of inulin to Eudragit RS was varied to create films with different degree of hydrophilicity. The phase behavior study revealed that blends of inulin and Eudragit RS are phase separated systems. The film permeability was studied by determination of the permeability coefficient of caffeine and the fraction of inulin that was released from the films in a buffer solution with or without inulinase was quantified. Together with the morphology characterization of the Inu-ERS films with and without incubation in the enzyme solution, these results suggest that the action of the enzyme was only limited to the fraction of inulin released in the buffer solution. Inulin fully embedded in the Eudragit RS matrix was not degraded. The permeation of the model drug caffeine occurred in the phase-separated film as a result of pores formed as a consequence of inulin release. The inulin to Eudragit RS blend ratio and the molecular weight of inulin affected the percolation threshold, the release of inulin, the morphology of the film formed thereafter and the connectivity of the formed water channels, thus influencing the drug permeation properties.

High moisture extrusion of meat analogues using mung bean (Vigna radiata L.) protein and flour blends: investigations on morphology, texture and rheology

SummaryHigh moisture meat analogues (HMMA) from the blends of mung bean protein isolate (MPI) and mung bean flour (MF) at different MF contents (10%, 20% and 30%) were prepared using high moisture extrusion (HME) and die texturisation. Pure MPI could not be extruded and texturised. Therefore, MF was added to improve the extrudability and to assist in the texturisation of HMMA. Rheological analysis performed under a range of simulated conditions in the cooling die demonstrated the decrease in both storage and loss moduli of the blend systems as compared to pure MPI, which explained the flow capability and extrudability of the blends during die texturisation. The effect of blend compositions on morphology and texture of the extrudates was investigated. All blend extrudates showed an anisotropic layer structure with a less pronounced velocity profile with increasing MF content. The microstructure of these extrudates revealed the presence of a multiphase system of the remaining MF fragments dispersed in a continuous protein matrix, thereby facilitating phase separation, loosening the protein structure and decreasing textural properties of HMMA as MF content increased. The results demonstrate that the blend of MPI and MF is a promising ingredient to prepare mung bean‐based HMMA with the customised texture properties.

Effect of Blend Composition on Barrier Properties of Insulating Mats Produced from Local Wool and Waste Bast Fibres

This paper concerns the management of natural waste fibres. The aim of this research was the production of multifunctional acoustic and thermal insulation materials from natural protein and lignocellulosic fibre wastes, according to a circular bioeconomy. For the manufacture of the materials, local mountain sheep wool and a mixture of bast fibre waste generated by string production were used. Insulating materials in the form of mats produced by the needle-punching technique with different fibre contents were obtained. The basic parameters of the mats, i.e., the thickness, surface weight and air permeability were determined. To assess barrier properties, sound absorption and noise reduction coefficients, as well as thermal resistance and thermal conductivity, were measured. It was shown that the mats exhibit barrier properties in terms of thermal and acoustic insulation related to the composition of the mat. It was found that mats with a higher content of the bast fibres possess a greater ability to absorb sounds, while mats with higher wool contents exhibit better thermal insulation properties. The produced mats can serve as a good alternative to commonly used acoustic and thermal insulating materials. The production of the described materials allows for a reduction in the amount of natural fibre waste and achieves the goal of "zero waste" according to the European Green Deal strategy.

Open-Celled Foams from Polyethersulfone/Poly(Ethylene Glycol) Blends Using Foam Extrusion.

Polyethersulfone (PESU), as both a pristine polymer and a component of a blend, can be used to obtain highly porous foams through batch foaming. However, batch foaming is limited to a small scale and is a slow process. In our study, we used foam extrusion due to its capacity for large-scale continuous production and deployed carbon dioxide (CO2) and water as physical foaming agents. PESU is a high-temperature thermoplastic polymer that requires processing temperatures of at least 320 °C. To lower the processing temperature and obtain foams with higher porosity, we produced PESU/poly(ethylene glycol) (PEG) blends using material penetration. In this way, without the use of organic solvents or a compounding extruder, a partially miscible PESU/PEG blend was prepared. The thermal and rheological properties of homopolymers and blends were characterized and the CO2 sorption performance of selected blends was evaluated. By using these blends, we were able to significantly reduce the processing temperature required for the extrusion foaming process by approximately 100 °C without changing the duration of processing. This is a significant advancement that makes this process more energy-efficient and sustainable. Additionally, the effects of blend composition, nozzle temperature and foaming agent type were investigated, and we found that higher concentrations of PEG, lower nozzle temperatures, and a combination of CO2 and water as the foaming agent delivered high porosity. The optimum blend process settings provided foams with a porosity of approximately 51% and an average foam cell diameter of 5 µm, which is the lowest yet reported for extruded polymer foams according to the literature.

Phase morphology, mechanical, and thermal properties of fiber-reinforced thermoplastic elastomer: Effects of blend composition and compatibilization.

In this work, recycled high density polyethylene (rHDPE) was compounded with regenerated tire rubber (RR) (35–80 wt.%) and reinforced with recycled tire textile fiber (RTF) (20 wt.%) as a first step. The materials were compounded by melt extrusion, injection molded, and characterized in terms of morphological, mechanical, physical, and thermal properties. Although, replacement of the rubber phase with RTF compensated for tensile/flexural moduli losses of rHDPE/RR/RTF blends because of the more rigid nature of fibers increasing the composites stiffness, the impact strength substantially decreased. So, a new approach is proposed for impact modification by adding a blend of maleic anhydride grafted polyethylene (MAPE)/RR (70/30) into a fiber-reinforced rubberized composite. As in this case, a more homogeneous distribution of the fillers was observed due to better compatibility between MAPE, rHDPE, and RR. The tensile properties were improved as the elongation at break increased up to 173% because of better interfacial adhesion. Impact modification of the resulting thermoplastic elastomer (TPE) composites based on rHDPE/(RR/MAPE)/RTF was successfully performed (improved toughness by 60%) via encapsulation of the rubber phase by MAPE forming a thick/soft interphase decreasing interfacial stress concentration slowing down fracture. Finally, the thermal stability of rubberized fiber-reinforced TPE also revealed the positive effect of MAPE addition on molecular entanglements and strong bonding yielding lower weight loss, while the microstructure and crystallinity degree did not significantly change up to 60 wt.% RR/MAPE (70/30).

Compatibilization of PA6/ABS blend by SEBS-g-MA: morphological, mechanical, thermal, and rheological properties

Blends polyamide 6 (PA6) and acrylonitrile-butadiene-styrene (ABS) were compatibilized with a styrene–(ethylene–butene)–styrene triblock copolymer grafted with maleic anhydride (SEBS-g-MA). In particular, the effects of ABS (0–100 wt%) and compatibilizer (0, 8, and 16 wt%) content were studied. The blends were first prepared by twin-screw extrusion, and different specimens were prepared by injection molding. From the samples produced, the effects of blend composition on morphological, mechanical, rheological, and thermal properties are reported. The structural analysis confirmed that the original blend is immiscible but showed some compatibilization when in the presence of SEBS-g-MA. Incorporation of the compatibilizer and ABS showed negligible effect on the melting behavior of PA6. The compatibilized blends showed higher tensile strength compared with uncompatibilized ones. However, Young’s modulus decreased with increasing compatibilizer content. The mechanical results were confirmed by rheological measurements in terms of interaction between each components in the blend.

Effect of blend composition and related morphology on the quasi-static fracture performance of LLDPE/PP blends

In the present work, the effect of composition and related morphology on the fracture behavior of LLDPE/PP blends was thoroughly investigated. Fracture behaviors evaluated under quasi-static loading conditions and different fracture mechanics methodologies were applied to assess fracture toughness depending on the materials behavior. For pure PP and 2575 blend, J at instability was chosen whereas for blends which exhibited completely ductile behavior (such as LLDPE, 7525 and 5050), the EWF methodology was used. Fracture mechanisms were elucidated with the aid of scanning electron microscopy, and results correlated with blends morphology. It was observed that fracture properties are mostly dominated by the majority component properties. In addition, for the 5050 blend, the presence of a co-continuous morphology is responsible for the high scatter of experimental data obtained.

Effect of blend composition on characteristics and performance of Jatropha bio-epoxy/epoxy matrix in composites with carbon fiber reinforcement

Characteristics and performances of a blended jatropha bio-epoxy/epoxy as a matrix in carbon fiber reinforcement was studied. The amount of bio-epoxy was arranged from 0 wt%, 25 wt%, 30 wt%, 40 wt%, and 50 wt% of the total matrix. Several analyses were performed to characterize and observe their performance. Fourier transform infrared spectroscopy, thermal analysis, physical characteristics, flammability, and soil burial were conducted, as well as mechanical tests. The results showed that introducing bio-epoxy in the matrix changed characteristics and increased or decreased their performance. Blending more than 25 wt% of bio-epoxy led to improved thermal stability between 280 °C to 350 °C and better biodegradability. However, tensile and flexural strength as well as modulus of elasticity decreased once the proportion of bio-epoxy was greater than 25 wt%. The paper proposed an optimal amount of jatropha bio-epoxy so that an alternative biocomposite application could be introduced to minimize carbon footprint in the environment.

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

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

Investigating the Phase-Morphology of PLLA-PCL Multiblock Copolymer / PDLA Blends Cross-linked Using Stereocomplexation

ABSTRACTThe macroscale function of multicomponent polymeric materials is dependent on their phase-morphology. Here, we investigate the morphological structure of a multiblock copolymer consisting of poly(L-lactide) and poly(ε-caprolactone) segments (PLLA-PCL), physically cross-linked by stereocomplexation with a low molecular weight poly(D-lactide) oligomer (PDLA). The effects of blend composition and PLLA-PCL molecular structure on the morphology are elucidated by AFM, TEM and SAXS. We identify the formation of a lattice pattern, composed of PLA domains within a PCL matrix, with an average domain spacing d0 = 12 – 19 nm. The size of the PLA domains were found to be proportional to the block length of the PCL segment of the copolymer and inversely proportional to the PDLA content of the blend. Changing the PLLA-PCL / PDLA ratio caused a shift in the melt transition Tm attributed to the PLA stereocomplex crystallites, indicating partial amorphous phase dilution of the PLA and PCL components within the semicrystalline material. By elucidating the phase structure and thermal character of multifunctional PLLA-PCL / PDLA blends, we illustrate how composition affects the internal structure and thermal properties of multicomponent polymeric materials. This study should facilitate the more effective incorporation of a variety of polymeric structural units capable of stimuli responsive phase transitions, where an understanding the phase-morphology of each component will enable the production of multifunctional soft-actuators with enhanced performance.

A study on the thermophysiological and tactile comfort properties of silk/lyocell blended fabrics

Certain investigations on the thermophysiological and tactile comfort properties of silk/lyocell blended fabrics have been carried out. A series of yarns were produced as 100% silk (S 100), 75% silk and 25% lyocell (S/L 75:25), 50% silk and 50% lyocell (S/L 50:50), 25% silk and 75% lyocell (S/L 25:75) and 100% lyocell (L 100) and converted to woven fabrics keeping the same fabric set. FTIR study on silk, lyocell and silk/lyocell blended fabrics show the characteristic functional groups for the respective fabrics. The effects of blend compositions on thermophysiological and tactile comfort properties were examined and the results show that thermal resistance of the fabrics containing silk has a higher value in comparison with lyocell-rich blends. Water vapour permeability, absorbency and wickability for lyocell and lyocell-rich blends are found to be superior as compared to 100% silk fabrics. With respect to drape, bending length and crease recovery the lyocell rich fabrics are good in comparison with 100% silk fabrics. The results are discussed using one way ANOVA with 5% significant level. Keywords: silk, lyocell, blending, comfort, eco-friendly.

Modified ethylene‐propylene‐diene elastomer (EPDM)‐contained silicone rubber/ethylene‐propylene‐diene elastomer (EPDM) blends: Effect of composition and electron beam crosslinking on mechanical, heat shrinkability, electrical, and morphological properties

ABSTRACTIn this investigation, a gamma radiation‐induced methacrylic acid (MAA)‐grafted ethylene‐propylene‐diene elastomer (EPDM) was used as a third component (g‐EPDM) in silicone rubber (SiR)/ethylene‐propylene‐diene elastomer (EPDM) blends. These blends were electron beam (EB) crosslinked. The effect of blend composition, the presence of g‐EPDM, and EB crosslinking on the mechanical, heat shrinkability, electrical, and morphological properties of SiR/EPDM blends have been studied. To investigate the effect of grafted EPDM (g‐EPDM), 10 wt % of g‐EPDM was added to immiscible SiR/EPDM blends. Both silicone and EPDM are blended in different proportions (70:30 and 30:70) with and without g‐EPDM followed by compression molding. To improve the properties and investigate the crosslinkability of binary and ternary blends further, the SiR/EPDM blends were irradiated by electron beam at different doses (50, 100, and 150 kGy). The gel content was found to increase with EPDM content, the presence of g‐EPDM, and radiation dose. The addition of g‐EPDM led to improvement of tensile properties (tensile strength, Young's modulus, percentage elongation, and toughness), electrical properties, and shrinkability of blends. EB crosslinking further enhanced the above properties. Surface morphology (SEM) revealed that the presence of g‐EPDM and the incorporation of EB crosslinking improved the above properties of blends. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47787.

Morphology and Mechanical Properties of Polyamide 6/Acrylonitrile-Butadiene-Styrene Blends Containing Carbon Nanotubes

The blends of polyamide 6/acrylonitrile-butadiene-styrene (PA6/ABS), with added styrene-maleic acid copolymer (SMA) compatibilizer, were prepared through melt mixing in an internal mixer. The effects of blend composition and various process conditions, as well as the addition of multi-wall carbon nanotubes (MWCNTs) to the blends, on the morphology and mechanical properties were investigated. The morphology of the blends and blend nanocomposites were observed by scanning electron microscopy (SEM) and analyzed using an image analysis technique. The mechanical behavior of the blends was investigated by tensile and also impact testing. The results showed that the blend composition as well as the processing conditions significantly affected the morphology and mechanical properties of the PA6/ABS blends. Among the various compositions, the blend with 36 wt.% of ABS and 4 wt.% of SMA compatibilizer exhibited the best mechanical properties. Comparing various speeds and times of mixing, it was found that less mixing speed and longer mixing times resulted in the favorable morphology and conditions for achievement of the desired toughness for the polyamide 6. By adding different amounts of MWCNTs to the blends, it was found that the presence of the carbon nanotubes changed the viscosity of the resulting nanocomposite and thus changed the morphology. These nanocomposites also showed an improvement in mechanical properties. The MWCNTs acted as a second compatibilizer, resulting in a synergistic effect on the mechanical properties of the PA6/ABS blend nanocomposites.

Recycled polypropylene blends as novel 3D printing materials

Consumer-grade plastics can be considered a low-cost and sustainable feedstock for fused filament fabrication (FFF) additive manufacturing processes. Such materials are excellent candidates for distributed manufacturing, in which parts are printed from local materials at the point of need. Most plastic waste streams contain a mixture of polymers, such as water bottles and caps comprised of polyethylene terephthalate (PET) and polypropylene (PP), and complete separation is rarely implemented. In this work, blends of waste PET, PP and polystyrene (PS) were processed into filaments for 3D printing. The effect of blend composition and styrene ethylene butylene styrene (SEBS) compatibilizer on the resulting mechanical and thermal properties were probed. Recycled PET had the highest tensile strength at 35 ± 8 MPa. Blends of PP/PET compatibilized with SEBS and maleic anhydride functionalized SEBS had tensile strengths of 23 ± 1 MPa and 24 ± 1 MPa, respectively. The non-compatibilized PP/PS blend had a tensile strength of 22 ± 1 MPa. PP/PS blends exhibited reduced tensile strength to ca. 19 ± 1–3 MPa with the addition of SEBS. Elongation to failure was generally improved for the blended materials compared to neat recycled PET and PS. The glass transition was shifted to higher temperatures for all of the blends except the 50–50 wt. % PP/PET blend. Crystallinity was decreased for the blends, but was highest in the 75–25 wt. % PP/PS and the 50-50 wt. % PP/PET blend with SEBS-maleic anhydride. Solvent extraction of the dispersed phase revealed polypropylene was the matrix phase in both the 50–50 wt. % PP/PET and PP/PS blends.