Search Results (77)

Poly(trimethylene terephthalate) (PTT) is a thermoplastic polyester with a unique structure due to having three methylene groups in the glycol unit. PTT competes with poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT) in carpets, textiles, and thermoplastic materials, primarily due to the development of economically efficient synthesis methods. PTT is widely utilized in textiles, carpets, and engineering plastics because of its advantageous properties, including quick-drying capabilities and wrinkle resistance. However, its low melting point, resistance to chemicals, and brittleness compared to PET, have limited its applications. To address some of these limitations for targeted applications, PTT nanocomposites incorporating clay, carbon nanotube, silica, and ZnO have been developed. The distribution of nanoparticles within the PTT matrix remains a significant challenge for its potential applications. Several techniques, including sol–gel blending, melt blending, in situ polymerization, and in situ forming methods have been developed to obtain better dispersion. This review discusses advancements in the synthesis of various PTT nanocomposites and the effects of nanoparticles on the isothermal and nonisothermal crystallization of PTT. Full article

Halogenated flame retardants have been amongst the most widely used and effective solutions for enhancing fire resistance. However, their use is currently strictly regulated due to serious health and environmental concerns. In this context, phosphorus-based and mineral flame retardants have emerged as promising alternatives. Despite this, their combined use is neither straightforward nor guaranteed to be effective. This study scrutinizes the interactions between these two classes of flame retardants (FR) through a systematic analysis aimed at elucidating the antagonistic pathways that arise from their coexistence. Specifically, this study focuses on two inorganic fillers, mineral huntite and chemically precipitated magnesium hydroxide, both of which produce basic oxides upon thermal decomposition. These fillers were incorporated into a poly(butylene terephthalate) (PBT) matrix to be utilized as advanced-mattress FR coating fabric and were subjected to a series of flammability tests. The pyrolysis products of the prepared polymeric composite compounds were isolated and thoroughly characterized using a combination of analytical techniques. Thermogravimetric analysis (TGA) and differential thermogravimetric analysis (dTGA) were employed to monitor decomposition behavior, while the char residues collected at different pyrolysis stages were examined spectroscopically, using FTIR-ATR and Raman spectroscopy, to identify their structure and the chemical reactions that led to their formation. X-ray diffraction (XRD) experiments were also conducted to complement the spectroscopic findings in the chemical composition of the resulting char residues and to pinpoint the different species that constitute them. The morphological changes of the char’s structure were monitored by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). Finally, the Limited Oxygen Index (LOI) and UL94 (vertical sample mode) methods were used to assess the relative flammability of the samples, revealing a significant drop in flame retardancy when both types of flame retardants are present. This reduction is attributed to the neutralization of acidic phosphorus species by the basic oxides generated during the decomposition of the basic inorganic fillers, as confirmed by the characterization techniques employed. These findings underscore the challenge of combining organophosphorus with popular flame-retardant classes such as mineral or basic metal flame retardants, offering insight into a key difficulty in formulating next-generation halogen-free flame-retardant composite coatings. Full article

This study investigates carbon fabric-reinforced thermoplastic composites produced via hot pressing, using Polyamide PA6 and Polybutylene Terephthalate (PBT) as matrix materials. These materials are increasingly utilized in the development of lightweight, high-performance, multilayer structures, such as aluminum-reinforced laminates, for automotive and aerospace applications. The mechanical properties, including tensile strength and stiffness, were systematically evaluated under varying loading conditions. The PBT-CF composite exhibited a 17% higher tensile strength and stiffness compared to the PA6-CF composite, despite the low carbon fiber content. This highlights the critical role of uniform fiber distribution in enhancing material performance. Slower loading speeds (1 mm/min) resulted in higher strength, emphasizing the influence of process parameters on mechanical behavior. Cyclic loading tests showed a gradual reduction in stiffness with increasing strain range, particularly for the CF-45° configuration. The warp and weft arrangement of the carbon fabric contributed to structural inhomogeneity but did not significantly affect the global mechanical properties. These findings demonstrate the suitability of PBT as a matrix material alongside PA6 for carbon fiber-reinforced thermoplastics, offering new possibilities for the design of advanced composite materials with tailored properties. Full article

This study explores the impact of blending polyethylene terephthalate (PET) with polybutylene terephthalate (PBT) on the thermal, structural, and mechanical properties of 3D-printed materials. Comprehensive analyses, including Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and mechanical testing, were conducted to assess the influence of blend composition. FT-IR confirmed that PET and PBT blend physically without transesterification, while TGA showed enhanced thermal stability with increasing PET content. XRD revealed that PET and PBT crystallize separately, with the crystallinity decreasing sharply for blends with more than 50% PET. The DSC results indicated that PET effectively slows down the crystallization kinetics of PBT, promoting cold crystallization. Mechanical tests demonstrated that the elastic modulus remains relatively unchanged, but the strain at break decreases with a higher PET content, indicating increased stiffness and reduced ductility. Overall, incorporating PET into PBT improves 3D-printability and dimensional stability, reducing warpage and enhancing print precision, making these blends advantageous for 3D-printing applications. Full article

Thermal and sound insulation play a vital role in today’s world, and nonwoven composite structures including microfiber layers provide efficient solutions for addressing these demands. In this study, the sound and thermal insulation properties of nonwoven composite structures, including single-layer meltblown, multilayer meltblown, hydroentangled, and nanofiber nonwoven inner layers, were compared statistically by using Design Expert 13 software. The inner layer type and outer layer type of the composite structures were considered as independent variables, and thickness, bulk density, air permeability, sound absorption coefficient, and thermal resistance of composite structures were evaluated as dependent variables during statistical analyses. The effects of layer types on dependent variables were investigated comparatively, and the best inner and outer layers for high sound and thermal insulation were determined. It was concluded that the developed nonwoven composites including hydroentangled and three-layered meltblown layers demonstrated superior sound absorption properties at low (changing between 48% and 70%) and moderate (ranging between 77% and 96%) sound frequencies, respectively, when compared to composites and materials including single-layer meltblown or nanofiber nonwoven structures reported in prior studies. Additionally, it can be inferred that the composite structures obtained in this study exhibited thermal resistance properties (0.49 to 0.73 m²K/W) comparable to those of commercial thermal insulation materials. Full article

Fogging in automotive headlamps is a significant issue that affects both aesthetics and functionality. This study investigates the use of graphene-based nanocomposites to mitigate fogging by enhancing the hygroscopic properties of polybutylene terephthalate/acrylonitrile styrene acrylate (PBT/ASA) composites commonly used in headlamps. The incorporation of functionalized graphene improved the tensile and flexural strength of the nanocomposites, though it led to a reduction in elongation and melt flow. Additionally, the solid lubrication properties and increased surface hardness of the graphene contributed to enhanced wear resistance. The presence of graphene in the nanocomposites also reduced moisture diffusion, lowering the rates of both hygroscopic and desorption when compared to commercial PBT/ASA composites. Furthermore, the nanocomposites exhibited a reduction in maximum moisture uptake. These improvements are expected to reduce the absolute humidity inside the headlamp, thereby effectively mitigating the fogging issue. Full article

In this work, a series of fluorinated microemulsions were synthesized using thermally decomposable N-dodecyl-N,N-dimethylamine N-oxide (LDAO) as surfactant. Then, polybutylene terephthalate nonwoven fabrics (PBT) were coated with microemulsion and heat-treated. Superhydrophobic and oil-repellent modified PBT with WCA (water contact angle) of about 152°, a sliding angle of about 2.1°, and oil repellency grade of 8 were prepared. The effect of surfactants on the surface wettability of hydrophobic materials was analyzed by TG-DTA, XPS, and WCA tests. The results show that surfactants decrease the WCA of hydrophobic materials, but LDAO can eliminate this effect by heat treatment. The anti-corrosion and permeability of LDAO coatings were compared with those of conventional fluorinated coatings through degradation and anti-permeability tests. It was shown that the LDAO fluorinated superhydrophobic coating is more resistant to corrosion by chemical solutions and significantly improves the impermeability of porous materials. Anti-fouling and self-cleaning tests showed excellent anti-fouling and self-cleaning properties on several common substrate surfaces modified with LDAO fluorinated microemulsions. It is expected that these new LDAO fluorinated microemulsions have promising applications in the preparation of corrosion-resistant surfaces and impermeable structures. Full article

In this study, two types of composites, polybutylene terephthalate (PBT) and epoxy resin (ER), reinforced with 20% of glass fiber (GF) are used as the comparative research objects. Their mechanical properties after thermal aging at 85~145 °C are evaluated by tensile strength and fracture morphology analysis. The results show that the composites have similar aging laws. The tensile strength of GF/PBT and GF/ER decrease gradually with the increase of aging temperature, while their elastic moduli are independent of the thermal treatment temperature. Scanning electron microscopy study of the fracture surface shows that separation of glass fiber from PBT and ER matrix becomes more obvious at higher aging temperature. The fibers on the matrix surface appear clear and smooth, and the whole pulled out GFs can be observed. As a main mechanical strength degradation mechanism, the deterioration of interface adhesion between the matrix and GF is discussed. A large difference in coefficients of thermal expansion of the matrix and GF is a main factor of the mechanical degradation. Full article

This study examines the process of using injection moulding to join two different materials to manufacture bi-component moulded products with improved performance characteristics. The two-component process, which combines the advantages of two different technologies—the high efficiency of the injection moulding process and the excellent mechanical properties of long glass fibre composites produced by resin transfer moulding (RTM) technology—offers a particular advantage and improved applicability of the prepared lightweight products in both the automotive and aerospace sectors. The composite studied here consists of Elium^® thermoplastic resin (30%) reinforced with unwoven glass fibre fabric (70%) using the RTM process. The Elium^® composite sample is consequently used as an insert overmoulded with polybutylene terephthalate (PBT) homopolymer reinforced with 20% w/w of short glass fibre through injection moulding. The influence of different mould temperatures and surface treatments on the adhesion between the materials used is investigated by evaluating the mechanical performance using tensile shear strength tests. It was found that while an increase in mould temperature from 40 °C to 120 °C resulted in a doubling of the initial average bond strength between untreated Elium^® RTM inserts and overmoulded PBT parts (0.9 MPa), sandblasting the inserts ensured a further tripling of the bond strength of the composites to a value of 5.4 MPa. Full article

Poly(L-Lactide) (PLA), a fully biobased aliphatic polyester, has attracted significant attention in the last decade due to its exceptional set of properties, such as high tensile modulus/strength, biocompatibility, (bio)degradability in various media, easy recyclability and good melt-state processability by the conventional processes of the plastic/textile industry. Blending PLA with other polymers represents one of the most cost-effective and efficient approaches to develop a next-generation of PLA-based materials with superior properties. In particular, intensive research has been carried out on PLA-based blends with engineering polymers such as polycarbonate (PC), poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT) and various polyamides (PA). This overview, consequently, aims to gather recent works over the last 10 years on these immiscible PLA-based blends processed by melt extrusion, such as twin screw compounding. Furthermore, for a better scientific understanding of various ultimate properties, processing by internal mixers has also been ventured. A specific emphasis on blend morphologies, compatibilization strategies and final (thermo)mechanical properties (tensile/impact strength, ductility and heat deflection temperature) for potential durable and high-performance applications, such as electronic parts (3C parts, electronic cases) to replace PC/ABS blends, has been made. Full article

To mitigate the environmental hazards aroused by fossil-based lubricants, the development of eco-friendly internal lubricants is imperative. Siloxane-based internal lubricants, widely applied as plasticizers in polymeric compounds, are a promising option. However, their impacts on the tribological properties of polymeric tribocomponents are still unclarified. Therefore, in the current study, a siloxane-based internal lubricant with the product name ‘EverGlide MB 1550 (EG)’ was dispersed into a polybutylene terephthalate (PBT)-based tribological composite to investigate whether the tribological properties of the composite can be optimized. A block-on-ring (BOR) test configuration was used for this purpose. It was found that the addition of EG to the composite significantly improved the tribological behavior; the improvement was particularly significant under lower load conditions (pv-product ≤ 2 MPa∙m/s). Compared to the reference PBT composite, the addition of EG reduced the friction coefficient (COF) by about 30% and the specific wear rate by about 14%. An accompanying surface analytical investigation using photoelectron spectroscopy to elucidate the effective mechanisms at the molecular level showed the availability of tribologically effective and free EG after its addition to the composite in the relevant tribocontact. Full article

Sound and heat insulation are among the most important concerns in modern life and nonwoven composite structures are highly effective in noise reduction and heat insulation. In this study, three layered nonwoven composite structures composed of a recycled polyester (r-Pet)-based thermo-bonded nonwoven outer layer and meltblown nonwovens from Polypropylene (PP) and Polybutylene terephthalate (PBT) as inner layers were formed to provide heat and sound insulation. Fiber fineness and cross-section of the thermo-bonded outer layer, fiber type (PP/PBT), areal weight (100/200 g/m²) and process conditions (calendared/non-calendared) of the meltblown inner layer were changed systematically and the influence of these independent variables on thickness, bulk density, air permeability, sound absorption coefficient and thermal resistance of composite structures were analyzed statistically by using Design Expert 13 software. Additionally, the results were compared with composite structures including an electrospun nanofiber web inner layer and with structures without an inner layer. It was concluded that comparable or even better sound absorption values were achieved with the developed nonwoven composites containing meltblown layers compared to nanofiber-included composites and the materials in previous studies. Full article

This study investigates the adhesion properties of polycarbonate (PC) and liquid silicone rubbers (LSR) through surface activation using ultraviolet C (UVC) radiation. While self-adhesive LSRs adhere easily to certain thermoplastic composites such as polybutylene terephthalate (PBT) and polyamides (PAs), bonding to PC typically requires surface treatment due to the lack of compatible functional groups. Previous methods like plasma or flame treatment have been effective, but the use of UVC radiation for surface activation remains unexplored. Through experiments, it was found that UVC surface activation, particularly with ozone-generating lamps, significantly enhances the peel strength between PC and self-adhesive LSRs. The study evaluates the impact of different irradiation times and lamp configurations on peel resistance, surface energy, and composite stability. Results show that UVC/ozone (wavelengths 254 nm and 185 nm) activation increases peel resistance, with distinct differences observed between LSR types. Additionally, the study examines the stability of UVC activation over time and under various storage conditions, highlighting its effectiveness for up to 36 months at room temperature. Furthermore, the relationship between surface energy and peel strength is analyzed, finding that UVC/ozone activation increases surface energy but does not consistently correlate with improved adhesion. The study concludes with a comparison of UVC/ozone activation to alternative surface treatment methods, emphasizing its advantages such as cost-effectiveness and stability while considering limitations regarding substrate compatibility and occupational safety aspects. Overall, UVC/ozone surface activation presents a promising approach for enhancing adhesion in PC–LSR composite systems and holds potential for applications across various industries. Full article

This work explores the definition and characterization of synthetic polymeric oligomers, chemical substances comprising a small number of repeated organic molecules. It highlights the lack of clarity surrounding the range of repeated units that can be classified as an oligomer, and how this definition is field-dependent. The present study focused on PET cyclic oligomers and revealed that the progression of the ring length from smaller to longer oligomers followed the well-known odd-even effect. This phenomenon affects the physical and chemical properties of oligomers and can also be observed with analytical techniques such as differential scanning calorimetry (DSC), high resolution mass spectrometry (HR-MS) and NMR. Similarities between PET and PBT oligomers were also observed, and an alternative potential definition for oligomers in the polymeric field is suggested based on physical behaviour of the longer cyclic oligomers. Full article

The multicomponent injection molding of liquid silicone rubbers (LSR) with thermoplastics, such as polybutylene terephthalate (PBT) or polyamide (PA), is a state-of-the-art technique and is used in the manufacturing process for many components in the automotive industry and in the field of sanitary engineering. Standard thermoplastics, such as acrylonitrile butadiene styrene (ABS), cannot be bonded with silicone rubbers in injection molding because of their low heat deflection temperature. In this study, we investigated ABS grades approved for medical applications to show how dynamic mold heating and various pretreatment methods for thermoplastic surfaces can be used to produce ABS-LSR test specimens. In addition, such components’ sterilization effect on the adhesive bond will be shown. Full article