Neat PET Research Articles

Expanded charring flame retardant effect of caged polysilsesquioxane containing Schiff base structure on poly(ethylene terephthalate) combustion

Via a hydrolytic condensation reaction, we successfully synthesized polyhedral oligomeric silsesquioxane containing Schiff base structures (NSPOSS). These were then incorporated into the PET matrix through melt blending, aiming to bolster the flame retardancy of poly(ethylene terephthalate) (PET). The interaction force between NSPOSS and PET was analyzed by simulation of NSPOSS pulling out in PET via MS8.0. Additionally, NSPOSS exhibits excellent flame retardancy and smoke suppression. For PET-10wt%NSPOSS, the peak heat release rate (pk-HRR), the total heat release (THR), the total smoke release (TSR), peak smoke release rate (pk-RSR), and the highest smoke density peak (Ds max) decreased by 60%, 14%, 57%, 42% and 59%, respectively, compared to neat PET. Moreover, PET-NSPOSS composites exhibit char expansion during combustion, for which we propose a charring mechanism. The newly prepared NSPOSS can be applied in various resin matrices, offering promising prospects for practical applications.

Recyclability of elastomer toughened recycled poly(ethylene terephthalate): The effect of grinding-extrusion-injection moulding on the mechanical and morphological properties of the blend

Reprocessing potential of recycled poly(ethylene-terephthalate) (RPET)/ethylene-butyl-acrylate-glycidyl methacrylate (EBA-GMA) blends was investigated. PET flakes from food packaging were compounded with 0, 5, 10, 15 and 20 % EBA-GMA. Injection moulded specimens were produced, and some of the specimens were grinded, and reproduced to simulate real reprocessing. It was revealed by scanning electron microscopy that the distribution and particle size of the elastomer did not change notably after recycling. Noticeable degradation of the polymer matrix was observable after every processing step. Such deterioration of PET resulted in higher crystallinity and rigid amorphous fraction, as found by differential scanning calorimetry, which ultimately led to higher storage modulus, while the notched impact strength and elongation at break decreased. Nevertheless, the mechanical performance of the reprocessed RPET/EBA-GMA blends still significantly outperforms that of the neat PET recyclate. The degree of chain breakage was found to be the primary factor determining the recyclability of RPET/EBA-GMA blends.

Improved crystallization behavior and enhanced impact strength of melt processed poly(ethylene terephthalate)/UiO-66 nanocomposites

The present research aimed to investigate the influence of Zr-based metal-organic framework, i.e. UiO-66, on the performance of poly(ethylene terephthalate) (PET) by the melt mixing method. PET/UiO-66 nanocomposites were prepared at 0.25, 0.5, 1, and 2 wt% of UiO-66. FESEM microphotographs showed the success of the melt mixing method in the fine dispersion of UiO-66 within PET. Additionally, XRD patterns confirmed that UiO-66 retained its structure after melt mixing at 260 °C. DSC analysis suggested that UiO-66 acted as a nucleating agent with a best performance at 1 wt% loading, i.e. 45 % decrease in the crystallization half-time and 11 % increase in the crystallization temperature. Furthermore, the PET/UiO-66 nanocomposites exhibited an improvement in char formation and resistance to complete thermal degradation at high temperatures compared to neat PET. The inclusion of UiO-66 in PET increased the impact strength with a maximum value at 0.5 wt% loading, e.g. more than twice neat PET. In addition, DMTA results indicated that UiO-66 acted as a strengthening agent in PET. Rheological investigations revealed that PET/UiO-66 exhibits the non-Einstein-like viscosity behavior in which the complex viscosity decreased by increasing UiO-66 content. We reasoned that behavior mainly to the flexible nature of the UiO-66 particles. Although all the samples showed almost Newtonian behavior at 260 °C in frequencies between 0.03 Hz and 100 Hz, PET/UiO-66 (0.5) presented the shear thinning behavior. This was ascribed to the good dispersion with the strong interfacial interaction, leading to a microstructure with yield stress.

Construction of catalyst-free, smoke suppression flame retardant PET fiber via bifunctional metal-organic framework

This work prepared a catalyst-free fire retardant PET fiber by developing a Co-based metal-organic framework (Co-MOF), which synthesized in a facile one-step hydrothermal method. With merely addition of 0.4wt% Co-MOF into PET, the LOI value of PET composites reached to 28.0%, the peak heat release rate (pHRR) and total smoking production (TSP) were decreased by 36.97% and 20.75%, respectively. Compared with traditional antimony trioxide catalyst, Co-MOF could shorten the esterification and polycondensation time by 16% and 12%. The char formation, which increased by 44.6% compared with that of neat PET from thermogravimetric analysis (TGA), played the key role in imparting PET with superior fire safety. The research on the flame retardant mechanism shows that Co-MOF plays a role in both the gas phase and the condensed phase. Besides, the mechanical and spinnability of PET-0.4Co-MOF was improved. After heat-setting the as-spun fiber by 3.5 times of draft, its breaking strength and the breaking elongation reached 3.52 cN/dtex and 29.70%, respectively.

Thermochromic and temperature regulation properties of phase change materials derived from polymer composites loaded with VO2 particles

AbstractThis research work concerns the development of phase change materials based on poly(ethylene terephthalate) (PET) mixed with vanadium dioxide particles (VO2). Monoclinic VO2 particles were synthesized via a hydrothermal process followed by modification of the particle surface with a silane coupling agent, namely 3‐(aminopropyl) triethoxysilane (APTES). After that, the metal oxide particles were mixed with PET flakes, derived from used PET bottles, in an internal mixer. In this study, the effects of surface modification and concentrations of VO2 particles on thermomechanical and optical properties of the composites were investigated. From the DSC results, it was found that the percentage crystallinity of PET increased after loading with VO2. This indicates that VO2 can act as a nucleating agent inducing the crystallization of the PET chains. From the scanning electron microscopy with energy dispersive X‐ray spectroscopy (SEM–EDX) images, better dispersion of VO2 particles in the PET matrix was noticed when the surface‐modified VO2 particles were used as a replacement for the normal VO2 particles. This contributed to the greater percentage of visible light transmittance through the composite sheets. Thermogravimetric analysis (TGA) profiles of both PET and PET/VO2 specimens are similar, indicating that the VO2 did not accelerate the thermal decomposition of the PET. When the specimens were exposed to an IR lamp, it was found that the temperature behind the PET/VO2 sheets dropped when compared to that of the neat PET sheets. Some shrinkage and deformation of the PET/VO2 specimens were also noticed. The higher the VO2 loading, the greater the deformation. The effect was ascribed to the fact that the actual temperature was above the critical transition temperature of VO2. Consequently, the NIR transmittance was suppressed at the expense of the greater NIR absorbance by the VO2 phase in the composites. Finally, when the specimens were exposed to solar irradiation at ambient temperature, the temperature underneath the PET/VO2 specimens became greater than that of the control specimen (the neat PET). The result was discussed in the light of the emissivity of VO2 at ambient temperature, which is considerably low. Overall, this study demonstrates that PET/VO2 can exhibit both cooling and warming effects, depending on the ambient temperature in relation to the critical transition temperature (Tc) of VO2.

Carbon Dots as smoke suppression agents for the reduction of CO release in combustion and improvement of UV resistance towards Phosphorus-containing polyester

2-Carboxyethyl(phenyl) phosphinic acid (CEPPA) is an effective phosphorus-containing flame retardant for PET. However, the release of poisonous and harmful smoke increases when CEPPA is added to PET matrix (CEPPA-PET) during the combustion process. To address this, biomass gelatin-based Carbon Dots (gCDs) was adopted as nontoxic green smoke suppression agent. When the gCDs was copolymerized into CEPPA-PET matrix by in situ polymerization (CEPPA-gCDs-PET), the peak smoke production rate was reduced by 59.38% and the CO yield was decreased by 13.83%. It was found the limited oxygen index of CEPPA-gCDs-PET rose to 31% from 21% and could achieve a V-0 rating in the UL-94 test when the content of gCDs and CEPPA were only 1.0 wt% and 5.0 wt%, respectively. What is more, in comparison with neat PET, the peak heat release rate significantly decreased by 42.66% and the total heat release was reduced by 48.10%, the peak smoke production rate is also reduced by 59.38%. Besides, the tensile strength of CEPPA-gCDs-PET increased by 11.93% for CEPPA-PET. At the same time, the addition of gCDs was beneficial for the improvement of UV resistance for CEPPA-PET, and the transmittance of sleeves prepared from the fiber of CEPPA-gCDs-PET is less than 5% from 240 nm to 400 nm. Thus, a higher efficiency flame retardant, mechanical enhancement and UV resistance system was constructed with only 5 wt% CEPPA and 1 wt% gCDs toward CEPPA-PET copolymer.

Thermal, morphological, rheological and deformation under mechanical loading analyses of recycled polyethylene terephthalates

Abstract This study aims at determining the mechanical deformation behavior of recycled poly (ethylene terephthalate) (r-PET) with digital image correlation (DIC) and finite element method (FEM), and to investigate the morphological, thermal, and rheological properties of r-PETs. Waste bottles were collected in trash bins and granulated with a cutter. Neat PET (n-PET) was also was used to determine accurately the changes in the properties of r-PET. PET test samples were obtained by injection molding at 260, 265, 270, and 275 °C. DIC and FEM were conducted to detect the deformation behavior of the PETs under mechanical loading. The data showed that the behavior of n-PETs and r-PETs were similar, and the stress distribution was found to densify in various areas for both PETs. The mechanical properties generally increased with increasing processing temperature, the best mechanical properties being obtained for thPETs processed at 275 °C. Scanning electron microscopy (SEM) analysis showed that the morphology of all the PETs were similar. Thermal stability was also found to be similar. The rheological moduli of n-PET processed at 260 °C were the highest, while processing r-PET at 275 °C improved its rheological properties.

Experimental and Theoretical Analysis of Mechanical Properties of Graphite/Polyethylene Terephthalate Nanocomposites.

In this work, graphite nanoplatelets (GNP) were incorporated into poly (ethylene terephthalate) (PET) matrix to prepare PET-GNP nanocomposites using a melt compounding followed by compression moulding and then quenching process. Both static and dynamic mechanical properties of these quenched materials were characterized as a function of GNP contents using dynamic mechanical thermal analysis (DMTA) and tensile machine, respectively. The results demonstrated that the addition of GNP improved the stiffness of PET significantly. Additionally, the maximum increase in the storage modulus of 72% at 6 wt.% GNP. The incorporation of GNP beyond 6 wt.% into PET decreases the storage moduli, but they remain higher than pure PET. The observed reduction could be due to agglomeration, resulting in poorer dispersion and distribution of higher levels of GNP into the PET matrix. In contrast to the results for moduli, tensile strength and elongations at break reduce with increasing the GNP content. For example, tensile strength reduced from ∼46 MPa (neat PET) to ∼39 MPa (−15%) for the nanocomposites containing 2 wt.% GNP. This reduction is accompanied by a decline in elongation at break from ∼6.3 (neat PET) to ∼3.4 (−46%) for the same nanocomposites. Such reductions are followed by a gradual decrease in upon further addition of GNP. These reductions indicate that increasing GNP loadings, results in brittleness in nanocomposites. In addition, it was found that quenched PET and composite samples were not fully crystallized after processing and therefore (cold) crystallized during the first heating cycle DMTA, as indicated by a rise in storage moduli above the glass transition temperature during the DMTA first heat. Furthermore, mathematical models based on non-linear theories are developed to capture the experimental data. For this, a set of mechanical stress-strain data is used for model parameters’ identification. Another set of data is used for the model validation that demonstrates good agreements with the experimental study.

Effects of novel functionalized magnesium phosphate monomers on the flame retardancy and mechanical properties of polyethylene terephthalate copolymers

In this study, inorganic magnesium hydroxide (MH) was modified by three phosphoric acids respectively to obtain three different novel functionalized monomers. The chemical structure and morphology of (Pn-MH) were analyzed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Further, functional monomers were introduced into the PET main chain structure. A new type of high-performance co-polyesters was successfully prepared. The specific structure of P1-MH-PET was characterized by 1H NMR spectroscopy. Thermal stability of Pn-MH-PETs was analyzed by thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). The flame retardant properties were evaluated by limiting oxygen index (LOI), vertical combustion test (UL-94) and cone calorimeter. The results show that the thermal stability and flame retardant properties of 5%Pn-MH-PETs are greatly improved. Among them, the best performance is 5%P1-MH-PET, LOI is 32.5%, UL-94 test reached V-0 grade. Compared with neat PET, the peak heat release rate (PHRR), peak smoke release rate (PSPR), carbon dioxide release rate (CO2PR) and carbon monoxide release rate (COPR) decreased by 57.0%, 38.1%, 54.6% and 57.3%, respectively. Fortunately, the mechanical properties of 5%P3-MH-PET were also improved.

Improve the compatibility and crystallization ability of polyhedral oligomeric silsesquioxanes and poly (ethylene terephthalate) by using transesterification method

AbstractIn the present study, an investigation was conducted on the effects of polyhedral oligomeric silsesquioxane (POSS) on the mechanical, morphological, and thermal properties of PET‐based nanocomposites. When the epoxy groups reacted with the PET end groups, the transesterification catalyst zinc acetylacetonate was introduced to facilitate the reaction between PET matrix and EPOSS. As clearly observed in the SEM image, 3 wt% POSS was added to PET matrix, the size of POSS particles was lower than 50 nm. As revealed from the EDX spectrum, the silicon signal was located in the EPOSS agglomerated particles and exhibited an even distribution in the entire PET matrix, which demonstrated a unique dispersion. Furthermore, it was reported that EPOSS exhibited nucleating agent performance, which suggested the higher temperature for melting crystallization (Up to 205.6°C while neat PET only reached 194.3°C). On the whole, EPOSS was revealed to act as a nucleating agent, whereas it could significantly facilitate the crystallization of PET by expediting the nucleation. Moreover, it could, to a certain extent, improve the mechanical properties of PET. These findings were attributable to the fact that PET and EPOSS exert a more comprehensive interface effect and a higher dispersion effect through the transesterification reaction.

The Effect of Nanosilicates on the Performance of Polyethylene Terephthalate Films Prepared by Twin-Screw Extrusion

Abstract Polyethylene terephthalate (PET) films were prepared by cast extrusion using a twin-screw extruder with a severe screw profile. The effect of an organically modified montmorillonite on thermal, mechanical, optical, and barrier properties of the PET films were investigated. Morphological characterization of the nanocomposite films was performed by employing wide angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) followed by image analysis. The results unfold a mixed morphology for the nanocomposite films with more than 95% exfoliated and intercalated silicate layer structures, depending on the screw rotation speed. The remarkable dispersion of the organoclay particles at the nano-level is discussed in terms of solubility parameter and favorable interactions between PET macromolecules and organic modifier of the nanoclay. The crystal content of the nanocomposite films and their cold and hot crystallization temperatures confirmed the role of silicate nanolayers as a heterogeneous nucleating agent. While all nanocomposite films exhibit higher haze values in comparison to the neat PET samples, incorporation of 2 wt% nanoclay brought about 25% increase in tensile modulus and barrier properties. A range of screw rotation speeds with optimized properties in terms of haze, morphology, thermal, mechanical, and barrier properties is suggested.

Effect of nucleating agents on the non‐isothermal crystallization and degradation kinetics of poly(ethylene terephthalate)

Poly(ethylene terephthalate) (PET) was synthesized by two steps, namely (a) transesterification and (b) polycondensation. Various analytical instruments were used for the characterization of neat PET. The sodium salt of nucleating agents added with PET was synthesized by the in‐situ method under the same experimental conditions. The influence of CO2Na, ONa, SO3Na, PO3Na on the crystallization properties of PET was tested. The aromatic SO3Na nucleated PET exhibited the highest crystallization temperature (Tc) value of 211.4°C with the degradation temperature (Td) value of 446.9°C. The energy of activation (Ea) for the degradation and crystallization of PET was determined using various kinetic models. The modified Avrami equation showed the 3D crystal growth of PET, which was further evidenced by polarized optical microscopy (POM). The second stage of degradation consumed a higher amount of thermal energy. The experimental results were compared with the literature values.

Effect of exfoliation medium on the morphology of multi-layer graphene oxide and its importance for Poly(Ethylene terephthalate) based nanocomposites

Poly(ethylene terephthalate) (PET)/multi-layer graphene oxide (mGO) nanocomposites were produced using the melt compounding technique, with the aid of a twin-screw extruder. The main goal was to investigate the effect of different exfoliation media on the morphology of graphene oxide and its effects, mainly on the mechanical performance of PET/mGO based polymer nanocomposites. Two different exfoliation media (water and ethanol) were used for the mGO synthesis. Based on each medium, nanocomposites with three different mGO contents (0.05 wt%, 0.1 wt%, and 0.3 wt%) were produced. When exfoliated in water, mGO sheets present larger lateral dimensions, i.e., higher surface area available to interact with polymer chains. All nanocomposites presented similar crystallinity, but with a slight increase related to the neat PET, indicating the nucleating effect of mGO. A theoretical model was used to predict the nanocomposites elastic modulus, justifying the experimental results. The biggest mechanical improvement was presented by a composite with low content of water-exfoliated mGO (0.1 wt%). The polymer tensile strength, strain at break, and toughness were improved by 19%, 238% and 590%, respectively. A significant reduction in the polymer dissipation factor (tanδ) with mGO content was also verified, indicating some confinement of polymeric chains due to interactions with the mGO sheets. The different surface fracture mechanisms presented by the nanocomposite with 0.1 wt% water-exfoliated mGO were verified, in which a good interface allowed greater release of strain energy. The XR-MT data confirmed that differences in mGO morphology can sensitively affect the final composite properties, characterising it as the driving force for mechanical improvements. Therefore, a melt compounded PET/graphene derivative composite is presented, exhibiting more promising results than what is already reported by solution mixed and in-situ polymerised composites. It was possible due to the strategic processing route utilised, in which the exfoliated mGO was pre-mixed with the polymer powder using the SSD technique.

Film Blowing of Linear and Long-Chain Branched Poly(ethylene terephthalate).

Film blowing of Poly(ethylene terephthalate) (PET) is challenging due its inherently low melt viscosity and poor melt strength. In this study, it is shown how the rheological properties of a commercial PET can be altered by reactive extrusion using either pyromellitic dianhydride (PMDA) or a multifunctional epoxy (Joncryl® ADR 4368) as chain extender, in order to improve the processing behavior during film blowing. The modified materials were characterized by shear and elongation rheometry and relevant processing characteristics, like melt pressure, bubble stability, and film thickness uniformity, were used to assess the influence of the type of modifier on processing and product performance. It is shown that PMDA is useful to increase the melt strength which leads to an improved bubble stability, while epoxy modified PET shows a reduced drawability that can cause problems at high take-up ratios. On the other hand, the epoxy modifier indicates a pronounced strain hardening during elongational deformation, and therefore leads to a better film thickness uniformity compared to the neat PET and the PET modified with PMDA. The differences with respect to processing performance are discussed and ascribed to the molecular structure of the materials.

Preparation and Properties of Graphene / Poly (Ethylene Terephthalate) Composite Fibers

A novel nanocomposite fibers were prepared from poly (ethylene terephthalate) (PET) and reduced graphene oxide (rGO) via melt spinning and their thermal and mechanical properties were investigated. Graphite oxide and rGO were characterized by the Fourier transform infrared spectroscopy (FT-IR). FT-IR spectrum of GO and rGO showed the same peak of O-H stretching of the hydroxyl and C=C stretching of aromatic rings as well as C-O stretching. The thermal stability of pristine PET and rGO/PET composite masterbatch was characterized by the thermogravimetric analysis (TGA). The thermal degradation temperature of PET and rGO/PET nanocomposite masterbatch was found at 413.9 °C and 418.1 °C, respectively. The mechanical properties of rGO/PET nanocomposite fibers were investigated and it was found that the mechanical properties were improved in all aspects comparing with neat PET fiber, including tensile strength, young's modulus and elongation at break.

Multiblock Copolymers for Recycling Polyethylene-Poly(ethylene terephthalate) Mixed Waste.

Plastic pollution is one of the most pressing global environmental issues we face today, in part due to the continued rise in production and use of disposable plastic products. Polyolefins and polyesters are two of the most prevalent polymers in the world accounting for ∼80% of total nonfiber plastic production. Recycling, despite being intrinsically environmentally friendly and sometimes economically viable, remains at a surprisingly low level (<9% in the U.S.) with most plastic waste ending up in landfills. One reason for this low rate of recycling stems from the challenge of recycling mixed waste streams and multicomponent plastics. In mixed waste streams, physical presorting of components prior to recycling requires significant effort, which translates to added cost. For multicomponent plastics (e.g., multilayer films such as food wrappers), the individual plastic components cannot be efficiently physically separated, and they are immiscible with poor interfacial adhesion when melt reprocessed. Thus, direct recycling of mixed plastics by melt reprocessing results in products that lack desired end-use properties. In this study, we describe the synthesis of novel poly(ethylene terephthalate)-polyethylene multiblock copolymers (PET-PE MBCPs) and evaluate their utility as adhesive tie layers in multilayer films and compatibilizer additives for melt reprocessed blends. PET and PE are targeted because they are two of the most prevalent commercial polymers in the world and are high volume waste streams. The work described here demonstrates two key findings. First, the PET-PE MBCPs serve as effective adhesive tie layers between neat PET/PE films with adhesive strength comparable to that of commercially available adhesives. Second, PET/PE (80/20 wt %) blends containing ∼0.5 wt % PET-PE MBCP were melt mixed to mimic recycling mixed plastic waste, and they were found to exhibit mechanical properties better than neat PET. Overall, this study demonstrates that PET-PE MBCPs could significantly enhance the ability to recycle PET/PE mixed waste streams by serving the role as both an adhesive promoting layer and a compatibilizer additive.

Improving the flame‐retardant property of bottle‐grade PET foam made by reactive foam extrusion

AbstractUpcycling of low intrinsic viscosity (IV) poly(ethylene terephthalate) (PET) grades, such as bottle‐ or recycled grades, by a reactive foam extrusion process, provides an appropriate alternative to high pricing, high IV grades commonly used for foaming applications. However, the drawback of bottle‐grade PET foams is its flame retardant (FR) performance. In this study, pyromellitic dianhydride was used as a chain extender to foam bottle‐grade PET. The influence of different FRs, containing halogenated (HFR) and four different phosphorous‐based types, on the processability and final foam properties was investigated. HFR showed better processability to achieve proper foams with fine morphology compared to P‐based FRs, where the FR content was adjusted between 2 and 5 wt%. However, HFR exhibited lower FR performance by cone calorimeter testing compared to the P‐based FRs and the commercial reference foam Kerdyn. Nonetheless, all of the FRs can only improve the time to ignition of the neat PET foams while the other values depend on the specific type of FR. In addition, all FR foams have improved mechanical properties more than twice in comparison to the neat PET foam.

Surface modification of highly hydrophobic polyester fabric coated with octadecylamine-functionalized graphene nanosheets.

This study focuses on the design of highly hydrophobic polyester fabrics (PET) coated with organophilic graphene nanosheets (G-ODA) through a simple, cost-effective and scalable coating method. The organophilic graphene oxide was successfully synthesized by covalently grafting a long chain fatty amine on its surface and was fully characterized by various physicochemical techniques. G-ODA was coated at different loadings onto the PET fabric ranging from 1 to 7 wt% to produce uniformly dispersed PET@G-ODA fabrics with multifunctional performances. FTIR has confirmed the formation of strong interfacial interaction between the PET and G-ODA functional groups. Moreover, the produced PET@G-ODA fabrics resulted in achieving enhanced thermal stability as well as excellent water repellency compared to the pristine PET. Water contact angle measurements showed a tremendous enhancement of surface hydrophobicity up to 148° with 7 wt% loading of G-ODA. Tensile strength tests revealed that our fabric exhibited excellent mechanical properties compared to neat PET. In addition, the designed PET@G-ODA fabrics demonstrated excellent oil/water separation efficiency for different oil/water mixtures. The obtained results are very promising in terms of designing and producing functional PET fabrics with improved thermal and surface proprieties.

Surface enrichment and nonleaching antimicrobial performance of polypropylene grafted poly(hexamethylene guanidine) (PP-g-PHMG) in poly(ethylene terephthalate)/PP-g-PHMG

Antimicrobial poly(ethylene terephthalate) (PET) materials are highly demanding in various applications in the industry. However, the combination of large-scale preparation, cost-effective and nonleaching characteristic still remains challenges. Herein, antimicrobial PET materials were prepared by an easy-to-scale-up melting blending between neat PET and polypropylene grafted poly(hexamethylene guanidine) (PP-g-PHMG). Such PET materials exhibited excellent antimicrobial activities, such as above 98.0% and 99.9% of inhibition rates against Escherichia coli and Staphylococcus aureus, respectively. Nonleaching characteristic was confirmed by the inhibition zone test. More importantly, the antimicrobial component enriched on the surfaces of PET materials due to the difference in the compatibility between PET matrix and PP-g-PHMG and the heterogeneous repulsive effect of crystallization. This work provides a facile and easy-to-scale-up way to obtain nonleaching antimicrobial PET.

Modification of poly(ethylene terephthalate) by copolymerization of plant-derived α-truxillic acid with excellent ultraviolet shielding and mechanical properties

Ultraviolet-shielding poly(ethylene α-truxillate-co-ethylene terephthalate) (PETT) was synthesized via the addition of α-truxillic acid (TA) as a third monomer in the copolymerization modification of poly (ethylene terephthalate) (PET). The effects of TA, with its semi-flexible/semi-rigid special structure, on the chemical structure, thermal properties, crystallization behavior, ultraviolet blocking properties, and mechanical properties of PETT were then investigated. Thermal analysis revealed that a small amount of TA significantly reduced the crystallinity and melting temperature of PETT but did not affect its thermal stability. Notably, the material exhibited excellent thermal properties in processing applications. With the addition of only 10 wt%, PETT could block ~100% of the ultraviolet spectrum (<400 nm), making up for the defect that pristine PET cannot shield the UV-A spectrum (320–400 nm). The yield stress also increased significantly from 29.8 MPa for the neat PET to 40.2 MPa for PETT (10 wt% TA). In addition, the TA is plant-derived and synthesized by environmentally friendly photodimerization reaction. A small amount of TA provides PET with excellent ultraviolet shielding performance and mechanical properties, broadening its application prospects in the field of anti-ultraviolet packaging materials.