PBT Matrix Research Articles

Unlocking interfacial synergies: In situ multi-step reaction-induced control for high-performance and functional polybutylene terephthalate/polyolefin blends from recycled sources

This investigation employed free radical melt grafting technology for the synthesis of (POE/R-LLDPE)-g-(GMA-co-St) graft copolymers. Subsequently, this graft copolymer was applied as a modifier for poly (butylene terephthalate) (PBT) resin. The effects of varying recycled linear low-density polyethylene (R-LLDPE) contents in the graft on the rheological behavior, thermal properties, mechanical properties, and toughening mechanism of PBT/(POE/R-LLDPE)-g-(GMA-co-St) blends were exhaustively explored. The findings revealed that glycidyl methacrylate (GMA) and styrene (St) were effectively grafted onto the poly (ethylene-octene) (POE) and R-LLDPE molecular chains. This process enabled the epoxy groups in the GMA of the graft to react with the terminal groups of the PBT resin, thereby enhancing its compatibility with PBT. The use of R-LLDPE-g-(GMA-co-St) or POE-g-(GMA-co-St) as singular modifiers did not produce optimal modification results. Conversely, the most effective modification of the PBT resin was observed when both were combined, indicating a pronounced synergistic modification effect. The optimal overall performance of the blend was noted when the R-LLDPE content in the graft copolymer was 50 wt%. This method significantly enhanced the toughness of the blend while preserving excellent thermal stability and mechanical strength, concurrently reducing the product cost. At this point, a high concentration of voids was observed in the stress-whitening area of the impact specimens. The PBT matrix displayed conspicuous shear yielding with a notably rough impact fracture surface, manifesting highly significant tough fracture characteristics.

Aggregation and Interfacial Adhesion of Nano-Sb2O3 Particles in Poly(Butylene Terephthalate) Composites: Effect of Surface Structure of the Nanoparticles

To study the effect of different surface structures on the aggregation level and interfacial adhesion, nano-Sb2O3 particles were treated with cetyltrimethylammonium bromide (CTAB), silane coupling agent KH550 and their compounds (CTAB + KH550). The surface properties and morphologies of the nano-Sb2O3 particles were characterized by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The aggregation level and interfacial adhesion of nano-Sb2O3 particles within PBT matrix were characterized by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC), and quantitatively evaluated by some semi-empirical parameters including aggregates size (Dagg ), real filling degree (Vre ), interfacial adhesion ( B ) and aggregated interfacial adhesion (Bagg ) from the tensile strength and the Young’s modulus measurements. The results showed that the highest interfacial adhesion and lowest aggregation level were obtained for the CTAB + KH550 modified nano-Sb2O3/PBT composites followed by the KH550 modified, CTAB modified and bare nano-Sb2O3/PBT composites, respectively.

Functionalized Poly(ethylene-octene)/Linear Low-Density Polyethylene Prepared by Melt Free-radical Grafting Reaction and Its Potential in Toughening Poly(butylene terephthalate) Resins

Glycidyl methacrylate (GMA) and styrene (St) were used as the graft monomer and co-graft monomer, respectively, and grafted onto poly(ethylene-octene) (POE) and linear low-density polyethylene (LLDPE) to prepare a series of GMA-functionalized (POE/LLDPE)-g-(GMA-co-St) graft copolymers. The copolymers were then blended with poly(butylene terephthalate) (PBT) to produce PBT/(POE/LLDPE)-g-(GMA-co-St) blends. The effects of grafting factors and copolymer content on the mechanical properties, thermal properties, rheology, morphology, and deformation mechanism of the blends were studied in detail. The results showed that GMA and St were successfully grafted onto the molecular chains of POE and LLDPE. In the grafting reaction, the best grafting degree and comprehensive performance were achieved when the amounts of dicumyl peroxide and GMA were 0.3 and 5 wt %, respectively, the mass ratio of GMA to St was 1:2, and the screw rotation speed was 60 rpm. By introducing graft copolymers into the PBT matrix, the toughness and thermal stability of the blends were improved. At the same time, the crystallinity and fluidity decreased, and the blends possessed the best mechanical properties when the copolymer content was 20 wt %, with the elongation at break and notched impact strength increasing to 409.98% and 945.90 J/m, respectively. Scanning electron microscopy analysis showed that the copolymers were uniformly dispersed in the PBT matrix. The principal toughening mechanisms were the shear-yielding properties of the PBT matrix and cavitation of (POE/LLDPE)-g-(GMA-co-St) phases.

Morphological, Mechanical and Thermal Properties of Polybutylene Tetrephthalate‐Polyester Based Thermoplastic Polyurethane Blends

AbstractPolybutylene tetrephthalate (PBT)‐polyester based thermoplastic polyurethane (TPU) blends with varying percentages of TPU (10 %, 20 %, 30 %, 40 %) were prepared in order to improve impact strength of PBT to enhance its applications. The blends were prepared by melt mixing using a twin screw extruder. Based on morphological images, impact strength analysis and dynamical mechanical analysis, TPU was well dispersed in PBT polymer matrix. Studies using Differential Scanning Calorimetry indicate a decrease in crsytallinity on addition of 30 % TPU in PBT. Thermogravimetric analysis demonstrates that addition of TPU in PBT matrix increases the char content. PBT and TPU have a good interfacial adhesion, according to SEM investigations. Mechanical characteristics demonstrate that the inclusion of TPU in PBT matrix resulted in a significant increase in impact strength of about 208 %, with minor changes in tensile strength and tensile modulus. Change in glass transition temperature of the optimised blend was measured using DMA.

Mechanical, thermal, tribological, and flammability properties of polybutylene terephthalate composites: Comparing the effects of synthetic wollastonite nanofibers, natural wollastonite, and graphene oxide

AbstractPolybutylene terephthalate (PBT) composites were prepared with 1.0 phr synthetic wollastonite nanofibers (SWN), natural wollastonite (NW) and graphene oxide (GO) to study the effect of different fillers on mechanical, thermal, tribological, and flammability properties. The properties of PBT composites are related to the size, structure, and interfacial adhesion of the fillers in PBT matrix. PBT/SWN demonstrated the highest tensile strength and Young's modulus (6% and 9% increment), followed by PBT/NW (1.3% and 7% increment) and PBT/GO (2% decrement and 4% increment). PBT/SWN gave the highest degradation temperature (409°C), followed by PBT/GO (404.7°C). The maximum enhancement in wear resistance (73%) by PBT/SWN and anti‐friction performance (26%) by PBT/GO evinced the excellent load‐bearing ability of SWN and the great lubricating effect of GO. PBT/NW had the lowest peak heat release rate, smoke, and carbon dioxide production rate. This study shows that PBT composites have great potential in different automotive applications.

Recycling of Wastes Deriving from the Production of Epoxy-Carbon Fiber Composites in the Production of Polymer Composites

The formulation of composites reinforced with shredded epoxy-carbon fibers wastes is investigated. Poly (buthylene terephthalate) PBT was selected as the matrix for the composites. In order to increase the interaction between the epoxy resin still coating the carbon fibers and the PBT matrix, polycarbonate (PC) was added either to the matrix formulation or as a waste coating. The flexural strength, impact strength, and dynamic-mechanical analysis of the new composites was investigated, as well as their microstructure by scanning electron microscopy. Experimental results show that the recycled fibers can be dispersed in both pure PBT and in its blend, enhancing the mechanical properties of the composites. An increase in the investigated properties is found specifically in the elastic modulus below 50 °C and in the impact strength. The extent of the increase depends on the obtained microstructure.

The Impact of Artificial Marble Wastes on Heat Deflection Temperature, Crystallization, and Impact Properties of Polybutylene Terephthalate.

As artificial marble is abundant and widely used in residential and commercial fields, the resource utilization of artificial marble wastes (AMWs) has become extremely important in order to protect the environment. In this paper, polybutylene terephthalate/artificial marble wastes (PBT/AMWs) composites were prepared by melt blending to maximize resource utilization and increase PBT performance. The research results showed that the filling of AMWs was beneficial to the improvement of PBT-related performance. X-ray diffraction analysis results indicated that after filling AMWs into the PBT matrix, the crystal structure of PBT was not changed. Heat deflection temperature (HDT) analysis results indicated that the HDT of PBT composites with 20 wt% AMWs reached 66.68 °C, which was 9.12 °C higher than that of neat PBT. Differential scanning calorimetry analysis results showed that heterogeneous nucleation could be well achieved when the filling content was 15 wt%; impact and scanning electron microscope analysis results showed that due to the partial core-shell structure of the AMWs, the impact strength of PBT was significantly improved after filling. When the filling amount was 20 wt%, the impact strength of the PBT composites reached 23.20 kJ/m2, which was 17.94 kJ/m2 higher than that of neat PBT. This research will not only provide new insights into the efficient and high-value utilization of AMWs, but also provide a good reference for improved applications of other polymers.

Study on recycling of Poly(butylene Terephthalate) and Polypropylene blend

Poly (butylene terephthalate) (PBT) is a breakable plastic because its high modulus value makes it unsuitable for specific applications. Recycling PBT is even more complicated when the color is no longer the original milky white. This study takes R-PBT from the brush hair scraps and blends with 10% Polypropylene (PP). The results show that the mold continually adhered to is challenging to inject the sample 100% R-PBT. The surface of sample R-PBT / 10% PP has a good gloss and smooth texture, while there is a high shrinkage rate in sample 100% PP. The hardness of sample R-PBT / 10% PP is increased when adding PP. In addition, sample 100% R-PBT has a distinctive shape with tiny fibers, while model 100% PP has a flat surface. For the R-PBT / 10% PP sample, the microstructure has two distinct regions: PBT matrix and PP dispersed-droplets.

Study on mechanical properties of nano-Sb2O3/BEO-PBT flame retardant composites reinforced by surface-modified basalt fiber

In this study, the cationic surfactant cetyl trimethyl ammonium bromide (CTAB) and silane coupling agent N-(β-aminoethyl)-γ-aminopropylmethylbimethoxy silane (KH602) were used as modifiers to improve the interfacial bonding strength between basalt fiber (BF) and PBT matrix. Using single modified and compound modified BF as reinforcing fillers, BF/nano-Sb2O3/BEO-PBT composites were prepared by injection molding. The structure characteristics of modifiers on the surface of BF were studied by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The mechanical, crystallization, thermomechanical properties and flame retardancy of BF/nano-Sb2O3/BEO-PBT composites were investigated using the tensile testing machine, impact testing machine, scanning electron microscopy (SEM), differential scanning calorimeter (DSC), dynamic mechanical analyzer (DMA), limiting oxygen index (LOI) and vertical combustion tester, respectively. The results showed that the CTAB and KH602 were successfully introduced into the surface of BF and the interfacial bonding strength between BF and PBT matrix was increased. The addition of BF did not reduce the flame retardancy of nano-Sb2O3/BEO-PBT composites. The tensile strength and Young's modulus of the BF/nano-Sb2O3/BEO-PBT composites were significantly improved and the notch impact strength was slightly increased with the use of modified BF. In terms of the mechanical properties of BF/nano-Sb2O3/BEO-PBT composites, the BF obtained an excellent enhancement effect on the composites when modifiers were applied by means of the compound modification with CTAB and KH602.

Impacts of Modified Graphite Oxide on Crystallization, Thermal and Mechanical Properties of Polybutylene Terephthalate.

In this study, the surface modification on graphene oxide (GO) was performed using octadecylamine (ODA). Furthermore, polybutylene terephthalate/GO (PBT/GO) composites were prepared to elucidate the role of GO surface modification on the mechanical performance, thermal stability and crystallization behavior. Results of Fourier transform infrared spectra (FT-IR), Raman spectrum, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and transmission electron microscope (TEM) revealed that ODA was successfully grafted on GO. Differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), tensile test, Izod impact strength test and TGA were carried out on the PBT/GO composites. Results indicated that the addition of raw GO can enhance the crystallization temperature and degree of crystallinity and can slightly improve the thermal stability and tensile strength of the composites. However, the impact strength and elongation at break were seriously decreased owing to the poor compatibility between the GO and PBT matrix. Once the modified GO was added, the crystallization temperature and degree of crystallinity were greatly increased. The tensile strength increased greatly while the elongation at break and Izod impact strength were efficiently maintained; these were evidently higher than those of PBT/raw GO. Moreover, thermal stability was greatly enhanced. SEM (scanning electron microscope) observation results on the impact-fractured surface clearly confirmed the improved compatibility between the modified GO and PBT matrix. A related mechanism had been discussed.

Fabrication and Properties of Modified Poly(butylene terephthalate) with Two‐Step Chain Extension

AbstractHigh‐viscosity, low‐crosslinked poly(butylene terephthalate) (PBT) from organic chain extenders and inorganic particles are prepared. PBT modification adopted from multifunctional, commercially available chain extension containing nine epoxy groups (ADR9) occurs in the first‐step chain extension; hydroxyl addition modified dioxazoline (BOZ) serves as the second step. Anion stratiform inorganic hydrotalcite (HT) is used to adjust the crystallization behavior and damp‐heat aging properties of PBT. The reaction between the chain extender and PBT end‐groups such as carboxyl (–COOH) and hydroxyl (–OH) enhances the interfacial bonding between the PBT matrix and dispersed HT phases. With a fraction of chain extenders in the PBT matrix, the chain‐extended PBT exhibits higher mechanical properties, intrinsic viscosity, average molecular weight, and melt viscosity than those of unmodified PBT. Damp‐heat aging resistance measurements show correlation with initial carboxyl content in the resin. Reducing the concentration of carboxyl end‐groups in the resin is shown to increase hydrolytic stability. The modified PBT resin can be used in optical fiber communication cable industry for its high level of damp‐heat aging resistance as well as good mechanic properties.

UV resistant PBT nanocomposites by reactive compatibilization and selective distribution of tailor-made double-shelled TiO2 nanohybrids

The application and service life of poly (butylene terephthalate) (PBT) is limited by its brittleness and ultraviolet (UV) instability. Titanium dioxide (TiO2) in PBT matrix can shield for UV light, but it triggers further photo-degradation of PBT via a photocatalytic effect. In this work, both toughness and against prolonged UV radiation of PBT from recycled source are significantly improved by reactive compounding with ethylene-vinyl acetate-glycidyl methacrylate copolymer (EVMG) and tailor-made double-shelled TiO2@SiO2-g-EVMG nanohybrids. The inner SiO2 shell prevents direct contact of TiO2 and the PBT matrix, while the grafted EVMG outer shell promotes a selective distribution and uniform dispersion of TiO2 in the EVMG phase only. Consequently, the impact toughness of PBT/EVMG/TiO2@SiO2-g-EVMG nanocomposites is 18 times higher than that of neat PBT. Moreover, the tensile strength and the elongation at break of the nanocomposites remain 95% and 87% respectively after 48-h accelerated UV irradiation. Meanwhile, 90% UV light can be shielded by the PBT/EVMG/TiO2@SiO2-g-EVMG nanocomposites. Therefore, this work provides a facile route to make PBT nanocomposites with superior mechanical and UV resistant performances, which may broaden the application range of (recycled) PBT and e.g. PBT/Polycarbonate blends.

Poly(Butylene Terephthalate) Filled with Sb2O3 Nanoparticles: Effects of Particle Surface Treatment, Particle Size, Particle Morphology and Particle Loading on Mechanical Properties of Composites

Poor dispersion of nanoparticles in polymer matrix would limit the development and application of particulate-filled polymer composites. Therefore, the Sb2O3 nanoparticles were functionalized by a combination of cetyltrimethyl ammonium bromide (CTAB) and silane coupling agent KH-560 via water bath modification method so as to improve the dispersion of Sb2O3 nanoparticles in poly(butylene terephthalate) (PBT) matrix and enhance the interfacial adhesion between nanoparticles and polymer matrix. Besides, the coating efficiency of compound modifiers on the surface of Sb2O3 nanoparticles was characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA). The Sb2O3 nanoparticles with different morphologies were systemically measured using transmission electron microscopy and dynamic light scattering measurement. The effects of particle surface treatment, particle size, particle morphology and particle loading on mechanical properties of composites were studied by the X-ray diffraction (XRD), tensile test machine and impact strength machine. The tensile strength of nanocomposites gradually increases with decreasing the particle size at the same amount of Sb2O3 nanoparticle fillers, which is attributed to improvement of interfacial contact area and stronger interfacial adhesion between Sb2O3 nanoparticles and PBT matrix. And the compound modified Sb2O3 nanoparticles are homogeneously dispersed in PBT matrix and play an important role in the properties enhancement. Moreover, taking consideration of the tensile and impact strengths, the optimal loading is 3 wt%.

Epoxy-based ionic liquid towards multi-walled carbon nanotubes/polybutylene terephthalate composite with excellent dispersion and conductivity behaviors

The Epoxy-based Ionic Liquid/carboxylated multi-walled carbon nanotubes/polybutylene terephthalate nanocomposites (EPIL/c-MWCNTs/PBT) were prepared through melt-blending method. Due to πcation-π interactions between EPIL and c-MWCNTs, and the reaction of a carboxyl group of PBT matrices with an epoxy group of EPIL, the c-MWCNTs displayed a homogeneous dispersion in the EPIL/c-MWCNTs/PBT, which could present better electrical properties than that of c-MWCNTs/PBT composites. SEM results presented that the compatibility between of c-MWCNTs and PBT had been improved due to the excellent dispersibility of c-MWCNTs in PBT matrix Meanwhile, the crystallization temperature of EPIL/c-MWCNTs/PBT also increased to 213.4 °C, higher than that of c-MWCNTs/PBT and pure PBT. Furthermore, the EPIL/c-MWCNTs/PBT nanocomposites showed excellent 3D conducting network and exhibited a low conductivity of percolation threshold when the loading of c-MWCNTs was only 0.7 wt%. The addition of EPIL and c-MWCNTs to PBT could effectively increase the dielectric constant and the uniformly dispersed c-MWCNT in low dielectric loss, which opened a new direction for the fabrication of EPIL/c-MWCNTs/polymer nanocomposites.

High-performance and functional PBT/EVMG/CNTs nanocomposites from recycled sources by in situ multistep reaction-induced interfacial control

Super-tough and antistatic poly (butylene terephthalate) (PBT) composites from recycled sources with carbon nanotubes were prepared by a multistep reactive compounding process. The PBT-modification was accomplished using epoxidized elastomers (EVMG), epoxidized multi-walled carbon nanotubes (e-CNTs) and epoxidized rheology modifiers (ADR). The reaction between epoxy and PBT-COOH (or –OH) groups enhanced the interfacial bonding between the PBT matrix and the dispersed EVMG and CNTs phases. Moreover, the distribution of CNTs is exclusively in the PBT phase. The presence of ADR resulted in a larger viscosity ratio of the PBT phase to the EVMG phase due to the PBT chain extension and branching, which led to a smaller EVMG particle size and a shorter inter-particle distance. Consequently, both the mechanical properties and the electrical conductivity of the PBT composites were considerably improved due to a synergistic effect of the EVMG and the ADR, e.g., the notched impact strength of the PBT composites reached up to 88 kJ/m2 and the percolation threshold value for conductive network was reduced by 27%. The super-tough and antistatic PBT composites designed in this study may broaden the application range of PBT in automotive and electrical applications.

Preparation of PBT/POE‐g‐GMA/PP ternary blends with good rigidity–toughness balance by core–shell particles

ABSTRACTCompared with poly(butylene terephthalate)/glycidyl methacrylate grafted poly(ethylene–octene) (PBT/POE‐g‐GMA) binary blends, supertough PBT‐based ternary blends with little rigidity loss were successfully obtained by adding rigid polypropylene (PP) into PBT/POE‐g‐GMA blends to construct core–shell particles during melt blending. The effects of PP content and type on the phase morphology and mechanical properties of the blends were systematically investigated. Theoretical predictions and scanning electron microscopy observation showed that a core–shell structure was formed in PBT matrix with PP as the core and POE‐g‐GMA as the shell. The mechanical property tests showed that POE‐g‐GMA and PP had significant synergistic toughening effect. When PP with high melt flow index (H‐PP) was used, PBT/POE‐g‐GMA/H‐PP (70/15/15) blends possessed the highest Izod notched impact strength, which was 1.9‐fold compared with PBT/POE‐g‐GMA (70/30) binary blends, while the tensile performance loss was little. The essential work of fracture tests was performed to evaluate the fracture resistance of different samples. The results demonstrated that PBT/POE‐g‐GMA/PP ternary blends possessed much better resistance to crack propagation than PBT/POE‐g‐GMA binary blends. The decrease of interparticle distance and the fibrillation of core–shell particles activated intense matrix shear yielding, which was the reason for the high crack resistance of ternary blends. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48872.

RVE modelling of short fiber reinforced thermoplastics with discrete fiber orientation and fiber length distribution

This study presents an analysis of modelling aspects on the effective composite properties of short glass fiber reinforced thermoplastics using representative volume elements (RVE). Although, many investigations were published showing effects of different modelling parameters of RVEs, we further elaborate in this contribution the parameters: influence of fiber packing, fiber shape, bonding of the fibers to the matrix, fiber length distribution and fiber orientation. The knowledge of these influences is used to determine the extent to which the increased modelling accuracy and thus the computational effort leads to an improved RVE’s forecast quality. This objective is achieved by creating and comparing different RVE models of a PBT-GF20 composite. The information required for the RVE models is obtained by experimental characterization of the PBT-GF20 and the PBT matrix material. It can be concluded based on the results of the numerical investigations in conjunction with the experimental tests of the composite that fiber packing, fiber length distribution, fiber orientation and fiber geometry are essential for a precise determination of the effective composite properties.

The crystallization, thermal and mechanical properties of nano‐Sb2O3 filled poly(butylene terephthalate)

Nano‐Sb2O3 particles were modified by a combination modifier of cetyltrimethyl ammonium bromide (CTAB) and KH‐560 via the mechanochemical method based on high‐energy ball milling. Then, the testing specimens of the nano‐Sb2O3/PBT composites of differing compositions were prepared by melting blending technology. The crystallization, thermal, and mechanical properties of composites were characterized by X‐ray diffraction, differential scanning calorimetry, thermogravimetric analyzer, and mechanical performance test. The tensile and impact fracture surfaces of composites were determined by scanning electron microscopy. Besides, the influence of the Sb2O3 nanoparticles surface modification on crystallinity, mechanical properties of the composites, and the interfacial adhesion between nano‐Sb2O3 and PBT was systematically investigated. The results indicate that the main crystalline characteristics of PBT matrix remain unchanged in the nanocomposites. However, the addition of nano‐Sb2O3 particles plays a heterogeneous nucleation and can effectively improve the crystallization of PBT matrix. In addition, the compound modification of the nano‐Sb2O3 can effectively enhance mechanical properties of the composites and interfacial interaction between nano‐Sb2O3 and PBT. The enhanced fracture properties in the nanocomposites were caused by the assisted void formation at the edge of the nano‐Sb2O3 particle. When the nano‐Sb2O3 mass fraction is 3%, the composites show excellent comprehensive performance. The interfacial adhesion parameter B and the half‐debonding angle θ of composites were assessed to quantitatively characterize the interfacial adhesion strength between nano‐Sb2O3 and PBT. Finally, the reinforcement and toughening mechanisms were described. J. VINYL ADDIT. TECHNOL., 26:268–281, 2020. © 2019 Society of Plastics Engineers

An insight into gas phase flame retardant mechanisms of AHP versus AlPi in PBT: Online pyrolysis vacuum ultraviolet photoionization time-of-flight mass spectrometry

As is well known, gas phase flame retardant mechanisms are very hard to be understood for the extremely intricate burning process but they are crucial for developing highly efficient flame retardants. Pyrolysis provides a valid way for this purpose because combustion proceeds after it. In this work, the pyrolysis behaviors of aluminum hypophosphite (AHP), aluminum diethylphosphinate (AlPi), poly(1,4-butylene terephthalate) (PBT) and PBT composites (with 10 wt% AHP or AlPi) were investigated by the fragment-free pyrolysis vacuum ultraviolet photoionization time of flight mass spectrometry (PY-PI-TOFMS) at different temperatures in real time. The gas phase flame retardant mechanism of AHP in PBT is proposed to be the flame inhibition effect of PH3, H3PO2 and P4 pyrolyzed from AHP. That of AlPi in PBT is speculated to be phosphorus-containing compounds and a kind of phosphorus radical pyrolyzed from AlPi as flame inhibitors and the promoted pyrolysis of AlPi by PBT matrix to be synchronous with it. The eight-membered cyclic non-covalent adduct of C2H5–(O=)P•–OH radical and a molecule of diethylphosphinic acid via intermolecular double hydrogen-bond interaction can produce PO type radicals more effectively in flame. Thermogravimetric analysis results are in accordance with those of pyrolysis. And the much better gas phase flame retardant effect of AlPi than AHP in PBT concluded from combustion tests are interpreted by pyrolysis results, which provides powerful guidance for developing highly efficient flame retardants.

Nucleation and mechanical enhancements in poly(butylene terephthalate) nanocomposites influenced by functionalized graphene oxide

Series of poly(butylene terephthalate) (PBT) nanocomposites are fabricated with polyethylene glycol methacrylate (PEGMA)-functionalized graphene oxide (GO) nanofillers (G-P) as the interfacial modifiers. PBT/G-P nanocomposites demonstrate good compatibility and interfacial interaction based on the uniform dispersed G-P nanofillers influenced by the grafted PEGMA chains. Crystallization behavior and nucleation density of PBT matrix get an increase and show a maximum at 1.5 wt% G-P nanofillers. Tensile strength and modulus of PBT/G-P nanocomposites first increase and then decrease with the varied G-P contents from 0.1 to 3.0 wt%, indicating the overloaded nanofillers impact the stress transfer. Against PBT/GO nanocomposites, PBT/G-P ones present 58% enhancement for the tensile strength, which is ascribed to the different interfacial compatibility afforded by the GO and G-P nanofillers. The present study demonstrates that it is a possible way to prepare high-performance PBT nanocomposites through the enhanced interfacial layer and nucleation behavior of polymer matrix.