Preparation and characterization of chitosan/α‐zirconium phosphate nanocomposite films

Nano‐fillers play an important role in the final structure and properties of nanocomposites. The objective of the work presented here was to prepare nanocomposite films of chitosan/α‐zirconium phosphate using a casting process, with α‐zirconium phosphate (α‐ZrP) as nano‐filler and chitosan as matrix. The effects of α‐ZrP on the structure and properties of the nanocomposites were investigated. X‐ray diffraction patterns showed that α‐ZrP crystals were intercalated by n‐butylamine. The results from scanning electron microscopy and transmission electron microscopy indicated that α‐ZrP could be uniformly dispersed in the chitosan matrix when α‐ZrP loading in the composites was less than 2 wt%. A strong interaction between α‐ZrP and chitosan formed during the film‐forming process. Tensile testing showed that the tensile strength and elongation at break of nanocomposite films achieved maximum values of 61.6 MPa and 58.1%, respectively, when α‐ZrP loading was 2 wt%. The parameter B calculated from tensile yield stress according to the Pukanszky model was used to estimate the interfacial interaction between the chitosan matrix and α‐ZrP. Films with a loading of 2 wt% α‐ZrP had the highest B value (3.2), indicating the strongest interfacial interaction. The moisture uptake of the nanocomposites was reduced with addition of α‐ZrP. It can be concluded that α‐ZrP as nano‐filler in a chitosan matrix can enhance the mechanical properties of nanocomposites due to the strong interactions between α‐ZrP and chitosan. Copyright © 2010 Society of Chemical Industry     

Synthesis of ionic liquid modified 1-D nanomaterial and its strategical distribution into the biodegradable binary polymer matrix to get reduced electrical percolation threshold and electromagnetic interference shielding effectiveness

Ionic liquid is increasingly being used as a chemical modulator of multi-walled carbon nanotubes (MWCNT). Here, we report the practical method for producing biodegradable electromagnetic interference (EMI) shield films made of thermoplastic polyurethane (TPU), polybutylene adipate-co-terephthalate (PBAT), and 1-(2-aminoethyl)-3-methyl-1H-imidazol-3-ium modified MWCNT (MIL). The field emission scanning electron microscopy study of cryo-fractured 50:50 PBAT/TPU blend giving co-continuous morphology and subsequent polymer EMI shield nanocomposite material had shown the co-continuous nanofiller distribution. The nanoparticles were chosen to be distributed in the PBAT portion, according to subsequent research employing HRTEM and DMA. The electrical percolation threshold (EPT) is determined to be situated within 1–3 wt% of nanoparticles loading as the remarkable shift in total EMI shielding efficiency from −14.6 dB (for 1 wt%) to −28.6 dB (for 3 wt%) of nanoparticle-loaded film at 10 GHz (in X-band region) for a 0.8 mm thick film reveals that the EPT is approximately at 2 wt% of nanoparticle loading. The effective EMI shielding of −37.3 dB was achieved by 10 wt% of MIL loading.     

Structure Stability,Flame Retardancy,and Antimicrobial Properties of Polyurethane Composite Nanofibers Containing Tannic Acid and Boron-Doped Carbon Nanotubes

A polyurethane (PU) composite nanofiber with superior flame retardancy and antimicrobial property is developed through the simultaneous incorporation of boron-doped carbon nanotubes (CNTs) and tannic acid (TA), resulting in excellent thermal, mechanical, and eco-friendly flame-retardant properties. The tensile strength and peak heat-release rate of the composite nanofiber increase with increasing filler content, with the optimal performance (7.38 ± 1.04 MPa and 254 W g⁻¹) being achieved at 3 wt% filler. Using a series of analytical techniques, it is demonstrated that the nanostructure of the neat PU completely collapses upon heating, transforming into a film-like structure; in contrast, a higher loading of nanofiller leads to a higher heat-shielding capability, thereby facilitating preservation of the composite nanofiber structure. Finally, the antibacterial activity is shown to increase as a result of the synergic effect of the boron-doped CNTs and TA.     

海泡石增强壳聚糖/玉米醇溶蛋白复合膜的制备及性能

采用流延成膜法制备了不同海泡石(SP)质量分数的壳聚糖(CS)/玉米蛋白(ZN)复合膜。研究了SP质量分数对CS/ZN复合膜机械性能和断面形貌的影响,分析了SP对CS/ZN复合膜的增强机理。扫描电子显微镜结果表明,SP粒子在复合膜中分散较好,CS与ZN之间有较好的相容性。随着SP质量分数增加,SP/CS/ZN膜拉伸强度先增加后减小,当SP质量分数为2%时,其拉伸强度达到最大值21.1 MPa,比纯CS/ZN提高了8.1%;而断裂伸长率随着SP质量分数先增加后降低,从15.3%下降为7.5%;同时复合膜的耐水性能上升,复合膜的吸水率随着SP质量分数增加先减小后增加,在8%时达到最小值。SP的引入导致复合膜的透光性能下降,SP质量分数为6%时在波长800 nm处光透过率下降约20%。     

Pea starch‐based composite films with pea hull fibers and pea hull fiber‐derived nanowhiskers

New applications of both pea hull fiber (PHF) and PHF‐derived nanowhiskers (PHFNW), isolated from PHF by acid‐hydrolysis, as fillers in starch‐based biocomposite films were explored in this work. Two series of films were prepared by blending pea starch (PS), respectively, with PHF and PHFNW. The effects of PHF and PHFNW as filler on the structure and properties of the composite films were comparatively investigated by observation of morphology and analysis of thermal, optical, and mechanical properties. The results revealed that the PS/PHFNW nanocomposite films exhibited improved physical properties over both the neat PS film and PS/PHF microcomposite films. The light transmittance at 800 nm, tensile strength, elongation at break, and Young's modulus were 56.0%, 4.1 MPa (Megapascal), 30.1%, 40.3 MPa, respectively, for the PS film without filler; 58.0%, 7.6 MPa, 41.8%, and 415.2 MPa for the PS/PHFNW film containing 10 wt% filler; and 37.2%, 2.8 MPa, 17.0%, and 29.8 MPa for the PS/PHF film containing 10 wt% filler. The improvement to the properties of PS/PHFNW nanocomposite films may be attributed to the nanometer size effect of PHFNW, which resulted in the homogeneous dispersion of PHFNW within the PS, and the strong interactions between the matrix and the nanoscale filler. POLYM. ENG. SCI., 2009. Published by the Society of Plastics Engineers     

High-density polyethylene reinforced by low loadings of electrochemically exfoliated graphene via melt recirculation approach

The purpose of the paper is to demonstrate the effectiveness of high-aspect ratio electrochemically exfoliated graphene (EEG) as a filler in high-density polyethylene (HDPE); we use an industrially viable polymer processing technique (melt blending with melt recirculation) to ensure excellent dispersion and reinforcement at low loadings. The effects of nanofiller loading were evaluated for two different HDPE grades with two different melt flow indices (MFI) based on crystallization, tensile, and rheological properties. The findings indicate improvements in mechanical properties (tensile modulus and tensile strength) for all HDPE/EEG nanocomposite samples; however, the reinforcement was more pronounced at 0.2 wt% loading, indicating a transition from excellent dispersion at lower loadings to aggregated at higher loadings. The low and high MFI HDPE/EEG nanocomposites at 0.2 wt% EEG loading displayed an improvement of 31% and 40% in tensile modulus and 19% and 33% in tensile strength, respectively. The improved mechanical response with higher MFI nanocomposites is likely due to enhanced dispersion associated with the lower melt viscosity. Similarly, the rheological results also showed maximum increase in storage and loss modulus at a loading of 0.2 wt% EEG. In conclusion, EEG can be an effective filler if proper dispersion is achieved, which is challenging at high loadings.     

蛭石/PBAT复合薄膜的制备与性能

使用蛭石（VMT）作为填料,以可生物降解的聚对苯二甲酸-己二酸丁二醇酯（PBAT）作为基体,采用熔融-吹塑法制备出蛭石/聚对苯二甲酸-己二酸丁二醇酯（VMT/PBAT）复合薄膜,并通过添加聚苯乙烯马来酸酐共聚物（SMA）作为相容剂制备了VMT/PBAT/SMA复合薄膜。对纯PBAT薄膜、VMT/PBAT和VMT/PBAT/SMA复合薄膜的热性能、流变性能、水蒸汽阻隔性能、断面微观结构和力学性能进行了测试。结果表明,相比纯PBAT薄膜,蛭石的填充使VMT/PBAT复合薄膜的热稳定性降低,相容剂SMA的添加增强了VMT/PBAT/SMA复合薄膜的热稳定性;蛭石的添加使复合薄膜的结晶度降低了约2%。水蒸汽透过量测试表明,两种复合薄膜水蒸汽阻隔性能符合国家标准;VMT的添加使VMT/PBAT复合薄膜的拉伸强度和断裂伸长率降低,而添加相容剂SMA使VMT/PBAT/SMA复合薄膜的拉伸强度和断裂伸长率相比VMT/PBAT复合薄膜提高约10 %。     

Synthesis and characterization of polyurethane/Mg‐Al layered double hydroxide nanocomposites

Layered double hydroxide (LDH) is a new type of nanofiller, which improves the physicochemical properties of the polymer matrix. In this study, 1, 3, 5, and 8 wt % of dodecyl sulfate‐intercalated LDH (DS‐LDH) has been used as nanofiller to prepare a series of thermoplastic polyurethane (PU) nanocomposites by solution intercalation method. PU/DS‐LDH composites so formed have been characterized by X‐ray diffraction and transmission electron microscopy analysis which show that the DS‐LDH layers are exfoliated at lower filler (1 and 3 wt %) loading followed by intercalation at higher filler (8 wt %) loading. Mechanical properties of the nanocomposite with 3 wt % of DS‐LDH content shows 67% improvement in tensile strength compared to pristine PU, which has been correlated in terms of fracture behavior of the nanocomposites using scanning electron microscope analysis. Thermogravimetric analysis shows that the thermal stability of the nanocomposite with 3 wt % DS‐LDH content is ≈ 29°C higher than neat PU. Limiting oxygen index of the nanocomposites is also improved from 19 to 23% in neat PU and PU/8 wt% DS‐LDH nanocomposites, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effects of mica modification with ethylene-vinyl acetate wax on the water vapor barrier and mechanical properties of poly-(butylene adipate-co-terephthalate) nanocomposite films

Poly-(butylene adipate-co-terephthalate) (PBAT) is one of the most popular raw materials for degradable plastic films because of its good biodegradability, ductility, and processability. However, the application of this material is limited by its unsatisfactory water vapor barrier property. This study aims to improve the water vapor barrier and mechanical properties of PBAT films by introducing mica modified by ethylene-vinyl acetate copolymer waxes (EVA-mica). The EVA-mica nanosheets showed a more uniform dispersion in the PBAT films than the mica nanosheets. The PBAT/EVA-mica films containing 2% EVA-mica demonstrated outstanding crystallinity, water vapor barrier, and mechanical properties compared with the pure PBAT films. Results showed a 20.23% increase in crystallinity, an 80.09% reduction in water vapor permeability, a 26.82% increase in tensile strength, and a 9.10% increase in tear strength. The enhanced water vapor barrier and mechanical properties of the PBAT/EVA-mica nanocomposite films are favorable for their future application as biodegradable films.     

Preparation and characterization of maleated thermoplastic starch‐based nanocomposites

Biodegradable nanoscale‐reinforced starch‐based products were prepared from an in situ chemically modified thermoplastic starch and poly(butylene adipate‐co‐terephthalate) (PBAT) through reactive processing. Natural montmorillonite (hydrophilic Cloisite Na) and organophilic Cloisite 30B were studied. In situ chemically modified thermoplastic starch (MTPS) was first prepared starting from (nano)clay (previously swollen in glycerol as plasticizer), and maleic anhydride (MA) as an esterification agent. Then, these nanoscale‐reinforced MTPS was reactively melt‐blended with PBAT through transesterification reactions promoted by MA‐derived acidic moieties grafted onto the starch backbone. The tensile and barrier properties of resulting (nano)composites were studied. High‐performance formulations with superior tensile strength (>35 MPa as compared with 16 MPa for the PBAT‐g‐MTPS copolymer) and break elongation (>800%) were obtained, particularly with Cloisite30B. Better water vapor and oxygen barrier properties of nanoscale‐reinforced MTPS‐g‐PBAT were achieved rather than the PRECURSORS. Wide angle X‐ray diffraction and transmission electronic microscopy analyses show that partial exfoliation of the clay platelets was observed within the PBAT‐g‐MTPS graft copolymer‐Cloisite 30B nanocomposite. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation of polybenzimidazole/functionalized carbon nanotube nanocomposite films for use as protective coatings

Functionalized multi‐walled carbon nanotubes (MWCNTs) via microwave‐induced polymerization modification route, and polybenzimidazole (PBI) nanocomposite films containing 0.1‐5 wt% functionalized MWCNTs were successfully synthesized. The functionalized MWCNTs were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and X‐ray photoelectron spectroscopy (XPS). The results verify that the polymer was successfully grafted to the MWCNTs with a polymer layer that was several nanometers thick. The TGA results showed that the quantity of the attached polymer reached approximately 9.4 wt%. The mechanical properties of the nanocomposite films were measured by tensile test and dynamic mechanical analysis (DMA). The tensile test results indicated that the Young's modulus increased by about 43.9% at 2 wt% CNT loading, and further modulus growth was observed at higher filler loading. The DMA studies indicated that the nanocomposite films had a higher storage modulus than pure PBI film in the temperature range of 30‐300°C, and the storage modulus was maintained above 0.82 GPa. Simulation results confirmed that the PBI nanocomposite films had desirable mechanical properties for use as a protective coating. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers.     

The role of nanofillers on (natural rubber)/(ethylene vinyl acetate)/clay nanocomposite in blending and foaming

Nanocomposite foams were fabricated from 60/40 wt% ethylene vinyl acetate (EVA)/natural rubber (NR) blends by using azodicarbonamide as a blowing agent. Two different nanofillers (sodium montmorillonite and organoclay) were employed to study their effects on foam properties. The results were also compared with conventional (china clay)‐filled foams. Transmission electron microscopy, X‐ray diffraction, scanning electron microscopy, and three‐dimensional Microfocus X‐ray computed tomography scanning analysis were performed to characterize the EVA/NR blend morphology and foam structures. The results revealed that the nanofiller acted as a blend compatibilizer. Sodium montmorillonite was more effective in compatibilization, generating better phase‐separated EVA/NR blend morphology and improving foam structure. Higher filler loading increased the specific tensile strength of rubber foams. The rubber nanocomposite foam showed superior specific tensile strength to the conventional rubber composite foam. The elastic recovery and compressive strength of the nanocomposite foams decreased with increasing filler content, whereas the opposite trend was observed for the conventional composite foams with china clay. The thermal conductivity measurement indicated that the nanofiller had better beneficial effect on thermal insulation over china clay filler. From the present study, the nanofillers played an important role in obtaining better blend morphology as compatibilizer, rather than the nucleating agent and the nanofiller content of 5 phr (parts by weight per hundred parts of rubber) was recommended for the production of EVA/NR nanocomposite foams. J. VINYL ADDIT. TECHNOL., 21:134–146, 2015. © 2014 Society of Plastics Engineers     

Biodegradable PBAT/Starch Nanocomposites

Starch-based biodegradable banocomposites of poly(butylene adipate-co-terephthalate) [PBAT] and organically modified nanoclays were prepared using melt intercalation technique in Haake Torque Rheocord 9000. Two different organically modified nanoclays Cloisite C20A and Cloisite C30B at various wt% (1, 3, 5) have been used for fabrication of nanocomposites. Starch was gelatinized to prepare thermoplastic starch (TPS) for increasing the compatibility with the PBAT matrix. Subsequently, films of PBAT/TPS blends at various TPS contents (10, 20, 30, 40) wt% and PBAT/TPS Organoclay biodegradable blend nanocomposites at different wt% of nanoclays were prepared using solvent casting method. The interfacial region between the biodegradable polymer matrix and the clays were also modified with grafting of Maleic anhydride (MA) with PBAT chains, during melt blending through two stage reactive extrusion process. Mechanical tests revealed an increase in tensile modulus and elongation at break with the incorporation of 30 wt% TPS and C30B nanoclay to the tune of 44.45% and 776.9% as compared with PBAT matrix. PBAT/TPS30 wt%/C30B3wt% shows maximum tensile modulus and elongation at break due to intercalation of silicate layers resulting from similarity in the surface polarity and interactions of C30B with TPS. Morphology of PBAT/TPS30%/C30B3% biodegradable blend nanocomposite studied using WAXD and SEM indicated intercalation and improved dispersion of TPS within PBAT with incorporation of C30B. Dynamical mechanical analysis of PBAT/TPS/C30B biodegradable blend nanocomposite revealed an increase of storage modulus and glass transition temperatures of PBAT with addition of nanoclays. Further Biodegradation test also confirmed higher biodegradability of PBAT in presence of TPS and C30B.     

Antimicrobial activity and biodegradation behavior of poly(butylene adipate‐co‐terephthalate)/clay nanocomposites

Poly(butylene adipate‐co‐terephthalate) (PBAT) nanocomposites films are prepared by a solution intercalation process using natural montmorillonite (MMT) and cetyltrimethylammonium bromide (CTAB)‐modified montmorillonite (CMMT). Cation exchange technique has been used for modification of MMT by CTAB and characterized by Fourier transform infrared analysis, thermo‐gravimetric analysis, and X‐ray diffraction (XRD) studies. CMMT gives better dispersion in the PBAT matrix than MMT and is confirmed by XRD and transmission electron microscopy. Because of better compatibility of CMMT, water vapor transmission rate of PBAT decreases more in the presence of CMMT than MMT. The biodegradability of PBAT and its nanocomposite films are studied in compost and from the morphological analysis it is apparent that the PBAT/CMMT shows a lower biodegradation rate in comparison to the PBAT/MMT. The antimicrobial activity of PBAT and its nanocomposite films is tested by an inhibition zone method. Because of the presence of the quaternary ammonium group of CTAB‐modified MMT, PBAT/CMMT nanocomposites show adequate antimicrobial activity. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40079.     

Effect of blend composition and organoclay loading on the nanocomposite structure and properties of miscible poly(methyl methacrylate)/poly(styrene‐co‐acrylonitrile) blends

Organically‐modified montmorillonite clay nanocomposites of poly(styrene‐co‐acrylonitrile) (SAN), poly(methyl methacrylate) (PMMA) and SAN/PMMA miscible blend are investigated. Structure characteristics at the nanoscale and microscale and thermal and tensile properties are studied as a function of polymer blend composition and filler loading fraction. Blend miscibility and T_g are unaffected by up to 10% by wt. organoclay. Thermal degradation stability increases with SAN content and exhibits an optimum value of clay loading. Stiffness shows significant improvement. Tensile strength and elongation‐at‐break suffer as a result of nanocomposite formation. Modulus shows a maximum enhancement of 57% (5 ± 0.06 GPa at 10 wt% filler, 20/80 SAN/PMMA) and varies linearly with clay fraction for all compositions of matrix phase. Predictions of Halpin–Tsai composite model are in excellent agreement with the experimental behavior over full range of polymer blend composition. Fundamental aspects of a polymer blend–clay nanocomposite are clarified, such as lack of additional synergy between clay platelets and matrix, and tensile ductility reduction, compared with polymer–clay system. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Preparation of Poly(Vinyl Alcohol) Nanocomposite Films Reinforced with Poly(Amide–Imide)/CuO Having N-trimellitylimido-L-valine Linkages for the Improvement of Mechanical and Thermal Properties

In this investigation, nanocomposite films were fabricated by dispersion of poly(amide–imide)/CuO nanocomposites as nanofiller in the poly(vinyl alcohol) matrix via an ultrasonic process. The nanofiller was prepared and mixed with PVA matrix. After dispersion of nanofiller into the poly(vinyl alcohol), the mechanical properties of the nanocomposites were improved. For example, the addition of 6 wt% nanofiller into the poly(vinyl alcohol) matrix enhanced the tensile modulus by 39%. The residual weight at 800°C was 7% for pure poly(vinyl alcohol) while the nanocomposites illustrated 12–19% residue at this temperature.     

Effect of different nanoparticles on thermal,mechanical and dynamic mechanical properties of hydrogenated nitrile butadiene rubber nanocomposites

Organically modified and unmodified montmorillonite clays (Cloisite NA, Cloisite 30B and Cloisite 15A), sepiolite (Pangel B20) and nanosilica (Aerosil 300) were incorporated into hydrogenated nitrile rubber (HNBR) matrix by solution process in order to study the effect of these nanofillers on thermal, mechanical and dynamic mechanical properties of HNBR. It was found that on addition of only 4 phr of nanofiller to neat HNBR, the temperature at which maximum degradation took place (T_max) increased by 4 to 16°C, while the modulus at 100% elongation and the tensile strength were enhanced by almost 40–60% and 100–300% respectively, depending upon nature of the nanofiller. It was further observed that T_max was the highest in the case of nanosilica‐based nanocomposite with 4 phr of filler loading. The increment of storage modulus was highest for sepiolite‐HNBR and Cloisite 30B‐HNBR nanocomposites at 25°C, while the modulus at 100% elongation was found maximum for sepiolite‐HNBR nanocomposite at the same loading. A similar trend was observed in the case of another grade of HNBR having similar ACN content, but different diene level. The results were explained by x‐ray diffraction, transmission electron microscopy, and atomic force microscopy studies. The above results were further explained with the help of thermodynamics. Effect of different filler loadings (2, 4, 6, 8, and 16 phr) on the properties of HNBR nanocomposites was further investigated. Both thermal as well as mechanical properties were found to be highest at 8 phr of filler loading. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Polyethylene with MoS2 nanoparticles toward antibacterial active packaging

Molybdenum disulfide (MoS₂) nanoparticles, obtained from liquid phase exfoliation in the presence of chitosan, were melt mixed with a linear low-density polyethylene (LLDPE) matrix to produce novel antimicrobial active packaging materials. The LLDPE/MoS₂ composites presented exfoliated nanoparticles forming aggregates that are well dispersed in the polymer matrix. These 2D-layered MoS₂ nanoparticles at concentrations of 0.5, 1.0, and 3.0 wt% rendered several functionalities to the LLDPE, as for example an antimicrobial behavior against Salmonella typhi and Listeria monocytogenes bacteria that can be explained not only by the photoactivity of the filler but also by changes in the composite surface. For instance, the composites presented a reduction in the water contact angle (i.e., an increased hydrophilicity) and relevant changes in the surface topography (i.e., reduced roughness) as compared with pure LLDPE. Regarding the barrier properties, while MoS₂ dramatically increased the water vapor permeation (WVP) of the polymer matrix, until 15 times for composite with 3.0 wt% of filler, the oxygen permeation decreased around 25%. All these novel functionalities in the nanocomposites were obtained without significantly affecting the tensile mechanical properties of the pure LLDPE matrix. These results show that MoS₂ is a promising filler for the development of antibacterial active packaging films with behaviors as similar as other 2D-layered fillers such as graphene derivatives.     

Study of silane treatment on poly‐lactic acid(PLA)/sepiolite nanocomposite thin films

Poly‐lactic acid (PLA) nanocomposite film was prepared with untreated and silane treated sepiolite through solution casting method. Sepiolite is found to be promising nano inorganic filler used to prepare biodegradable PLA nanocomposite films. The effect of sepiolite loading on the thermal, mechanical, gas permeability, and water vapor permeability (WVP) properties of the films was investigated. X‐ray diffraction analysis revealed the crystallinity index and well dispersed sepiolite in PLA/sepiolite thin films. By modifying sepiolite, depending on the nanoclay content, the mechanical properties of films were enhanced. PLA/sepiolite films exhibited improved gas barrier and WVP properties compared to neat PLA. The scanning electron microscope results demonstrated that there is a good interface interaction between sepiolite and PLA. The surface treatment of sepiolite increased the adhesion of the PLA matrix to the sepiolite nanoclay which yielded better mechanical properties of the films as compared to pure PLA. It was observed after 1.5% wt sepiolite, nano‐filler tended to agglomerate, therefore mechanical and barrier properties of films decreased. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41428.     

Effects of poly(butylene adipate‐co‐terephthalate) and ultrafined wollastonite on the physical properties and crystallization of recycled poly(ethylene terephthalate)

Recycled poly(ethylene terephthalate) (rPET), obtained mainly from postconsumer bottles, was melt‐mixed with either poly(butylene adipate‐co‐terephthalate) (PBAT) or PBAT plus ultrafine wollastonite (～5 μm) at different weight ratios on a twin‐screw extruder and then injection‐molded. Among the five rPET/PBAT blends (10–50 wt% PBAT) evaluated, the 80/20 wt% rPET/PBAT blend exhibited the highest tensile strength and degree of crystallinity, a slight increase in the tensile strain, and a remarkable increase in the melt flow index, but a lower tensile modulus and thermal stability with respect to the neat rPET. This blend was subsequently filled with four loading levels of wollastonite (10–40 wt%), where the tensile properties (modulus, strain at break, and strength) and thermal stability of the blend were all improved by the addition of wollastonite in a dose‐dependent manner. Based on differential scanning calorimetry analysis, the crystallinity of rPET in the rPET/PBAT/wollastonite composites decreased in the presence of wollastonite, accompanied with a noticeable increase in the glass transition, cold crystallization, and crystallization temperatures, but only a slight change in the melting temperature was noted compared with those of the neat 80/20 wt% blend. Moreover, the addition of wollastonite at 30 wt% or higher showed a strong reduction in the melt dripping of the composites during combustion. J. VINYL ADDIT. TECHNOL., 23:106–116, 2017. © 2015 Society of Plastics Engineers