Modified Polyphenylene Oxide Research Articles

Development of a solid food simulant to evaluate migration of chemicals from paper and board food contact materials to moist food

Food contact materials (FCMs) i.e. materials that food is packaged or handled in, must be safe for their intended use. European FCM legislation uses a risk-based approach, with a cornerstone of FCM’s safety evaluation being measurement of migration of substances from FCMs to food simulants. The standard methods mainly developed for plastic FCMs are not always suitable for less inert and moisture sensitive materials such as paper and board. However, these are becoming increasingly common as FCMs e.g. to replace single-use plastics. In addition, there is a drive to further use recycled materials. To support this development, new methods for assessing the safety of these materials are needed. In the present feasibility study, a hydrogel crosslinked through freeze-thawing of poly(vinyl alcohol) was evaluated as a food simulant for moist foods. The migration of surrogate compounds from a spiked paperboard to the hydrogel was determined and compared to the migration to a real moist food (a slice of apple), the commonly used modified polyphenylene oxide (MPPO) and a water extract. Migration of polar surrogates to the hydrogel correlated well with the migration to the apple slice. However, our results indicate that the hydrogel is less suitable as simulant for non-polar surrogates. Overall, the study demonstrates the potential of this hydrogel-based simulant for improving risk assessment of less inert FCMs.

Study of breakdown properties of SMA/MPPO composites

To improve the processability of polyphenylene oxide (PPO) and enhance its breakdown resistance, polystyrene (PS) with a mass fraction of 30% was added to PPO for blending modification, so that the melt flow rate of the modified polyphenylene oxide (MPPO) was increased to 14.8 g/10 min. Then the styrene maleic anhydride (SMA)/MPPO composites were prepared by melt blending and injection molding by adding different contents of SMA copolymer. The results showed that the anhydride group in SMA is grafted with PPO to form SMA-g-PPO copolymer, resulting in improved compatibility between PPO and PS. The best performance of the composites was obtained at a SMA content of 1 wt.%, with a DC breakdown strength of 24.6 kV·mm−1, which was 37.4% higher than that of MPPO, and an impact strength of 33.6 kJ·m−2, which was 18.7% higher than that of MPPO. The temperatures Td and T 50 corresponding to 1% and 50% mass loss increased by 46.15 °C and 11.48 °C, respectively, when the temperature was increased by 10 °C/min in the nitrogen atmosphere.

Bayesian inference-based prognosis of fatigue damage for MPPO polymer using Zhurkov fatigue life model

In this study, the fatigue damage prognosis of a modified polyphenylene oxide (MPPO) polymer is performed using a Bayesian framework, and a Zhurkov model-based dynamic fatigue life model is employed to obtain the probabilistic stress–cycle (P-S-N) curve. Activation energy and tensile tests are performed to determine the aleatory uncertainty of the lethargy coefficient of the Zhurkov fatigue life model. This uncertainty is quantified by performing sequential statistical modeling using experimental data with embedded scattering. The P-S-N curve is estimated using these data, and the Zhurkov fatigue life model is validated via the fatigue test. Furthermore, damage data are obtained via a low-cycle fatigue analysis in conditions identical to those of the fatigue test conducted on the specimen scale. Based on computational damage data, the initial model parameters of the fatigue damage model are obtained using the least-squares method. These model parameters are estimated while considering scattering by applying the Markov Chain Monte Carlo and particle filter. Therefore, the remaining useful life (RUL) of the MPPO, which depends on the amplitude stress, is predicted under the tension–tension fatigue loading ( R = 0), and the prediction accuracy of the RUL is evaluated using prognostics metrics.

Physical Properties of Modified Polyphenylene Oxide as a Composite Material for Hydrogen Fuel Cell Stack Enclosure Suitable for Injection Molding

There is an increasing need for securing development technology for suitable materials to obtain more productive and lightweight automobile parts, including hydrogen fuel cell stack enclosures. Due to the poor moldability of Poly-Phenylene Oxide (PPO), which excels in terms of mechanical, thermal, and electrical properties, studies are being actively conducted to commercialize modified-PPO (mPPO). However, there is a lack of studies regarding injection molding analysis for pre-verification of the suitability of injection molding in the process of developing engineering plastic resins. Thus, this study utilized the following procedure: (1) it measured the physical properties of mPPO, (2) it selected sample candidates, (3) it applied the Design Of Experiments (DOE) to conduct an injection molding analysis, and finally, (4) it proposed an enclosure-dedicated mPPO due to its suitability for injection molding. The results of this study demonstrated the excellent moldability of mPPO with a mixing ratio of PPO 50%/Poly-Amide66(PA66) 50% among 16 samples by investigating the fill time, deflection, time to reach ejection temperature, void phenomenon and cycle time. Therefore, mPPO with a mixing ratio of PPO 50%/PA66 50% will exhibit the best moldability and increased productivity in manufacturing enclosures.

Migration of mineral oil aromatic hydrocarbons (MOAH) from cardboard containers to dry food and prediction tool

This research aimed to study the migration of mineral oil aromatic hydrocarbons (MOAH) from primary carton packages to dry foods, using 16 aromatic hydrocarbons as model substances, covering a wide range of molecular masses and chemical structures. Migration experiments were performed using modified polyphenylene oxide as a food simulant and couscous and polenta as dry foods. The migration tests were carried out to simulate storage at room temperature for long periods and in hot food containers as the worst scenario. Multivariate analysis algorithms were applied to correlate and group the migration of model substances, and a partial least squares regression (PLSR) model was built to predict the worst-case migration. The results showed strong correlations in the migration patterns of the model substances, based on their volatility, food matrix, migration time and temperature. Different behaviour between the migration of the most volatile and the heaviest model substances was observed.

Release of Cinnamaldehyde and Thymol from PLA/Tilapia Fish Gelatin-Sodium Alginate Bilayer Films to Liquid and Solid Food Simulants, and Japanese Sea Bass: A Comparative Study.

This study aimed to develop an active biodegradable bilayer film and to investigate the release behaviors of active compounds into different food matrices. Cinnamaldehyde (CI) or thymol (Ty) was encapsulated in β-cyclodextrin (β-CD) to prepare the active β-CD inclusion complex (β-CD-CI/β-CD-Ty). The tilapia fish gelatin-sodium alginate composite (FGSA) containing β-CD-CI or β-CD-Ty was coated on the surface of PLA film to obtain the active bilayer film. Different food simulants including liquid food simulants (water, 3% acetic acid, 10% ethanol, and 95% ethanol), solid dry food simulant (modified polyphenylene oxide (Tenax TA)), and the real food (Japanese sea bass) were selected to investigate the release behaviors of bilayer films into different food matrixes. The results showed that the prepared β-CD inclusion complexes distributed evenly in the cross-linking structure of FGSA and improved the thickness and water contact angle of the bilayer films. Active compounds possessed the lowest release rates in Tenax TA, compared to the release to liquid simulants and sea bass. CI and Ty sustained the release to the sea bass matrix with a similar behavior to the release to 95% ethanol. The bilayer film containing β-CD-Ty exhibited stronger active antibacterial and antioxidant activities, probably due to the higher release efficiency of Ty in test mediums.

Preparation and Characterization of Glass-Fiber-Reinforced Modified Polyphenylene Oxide by a Direct Fiber Feeding Extrusion Process

Polyphenylene oxide (PPO) polymers have good mechanical, electrical, and thermal properties, but they have poor processability owing to their quite high melt viscosity. This hinders the manufacturing processes of fiber-reinforced thermoplastics that have enhanced mechanical and physical properties. Although PPO was modified by blending with polystyrene (PS) or polyamide to improve processability, the modified PPO (mPPO) still had a high melt viscosity compared with other polymers. Thus, the fiber-reinforced mPPO is manufactured by compounding with chopped fiber, while various methods are applied to manufacture the fiber-reinforced polypropylene and polyamide in order to improve properties. One of the methods is a direct fiber feeding method, which can keep the longer fiber length because of a direct and continuous roving yarn feeding without chopping. Therefore, the composite manufactured by the direct fiber feeding method is expected to improve the mechanical properties. Hence, this study aims to investigate the feasibility of a direct fiber feeding extrusion process for manufacturing glass-fiber-reinforced mPPO or GFmPPO. The manufactured GF/mPPO composites exhibited increased tensile and flexural properties as the fiber content increased up to 50 wt% of GF owing to the predominant effects of fiber content. Nevertheless, the larger core area in the cross-section micrograph of the tensile specimen of the GF/mPPO composite with 50 wt% of GF was observed to reduce the fiber efficiency factor for tensile strength. Meanwhile, the impact strength of the GF/mPPO composites decreased with increasing GF content. This is attributed to the insufficient fiber length for the impact strength. As the GF content increased, the glass transition temperature slightly decreased. This result was interpreted as being a result of thermal degradation during the extrusion process to manufacture the GF/mPPO masterbatch. The results of the dynamic mechanical analyses, e.g., storage modulus and tan δ, show the good correlation with the increased flexural modulus, the decreased glass transition temperature, and the impact strength as the GF content increased.

Migration of surrogate contaminants from paperboard to foods: Effect of food and surrogate properties

ABSTRACT The current research describes an alternative test method to evaluate the impact of food properties and compound characteristics on migration from paperboard to food. Tightly sealed bottles containing paperboard spiked with surrogate components as a donor, together with modified polyphenylene oxide (MPPO or Tenax®) or one of the nine considered foods as a receptor, were stored at 22°C. Instead of analysing the receptor, migration from donor to receptor was followed up by evaluating the recovery of surrogates from the donor over time, thus avoiding challenges in the analysis of the foods as such. Free fat content affected the migration more than the specific surface area of the food, reaching a plateau at fat contents >8.1%. The highest migration was observed to fatty foods such as biscuits (8% to 25% fat) and chocolate (40% fat). Intermediate migration occurred to starchy and particulate foods such as egg-based wheat pasta (2.6% fat), wheat flour (1% fat) and rice flour (0.5% fat). Low migration occurred in the case of paperboard in contact with wheat pasta (0.4% fat). Native starch was found to be more sensitive to migration than gelatinised starch. Volatility was identified as the most important characteristic of the migrating compounds. MPPO was considered as a suitable surrogate for dry foods as it did not underestimate migration in any case. However, for low-fat foods such as wheat pasta, clear overestimations could occur, but only for volatile surrogates with vapour pressure over 1.45 mTorr.

Influence of the Molecular Polyimide Brush on the Gas Separation Properties of Polyphenylene Oxide

A new hybrid gas separation membrane was prepared from poly(2,6-dimethyl-1,4-phenylene oxide) modified with graft copolyimide with side poly(methyl methacrylate) chains. The changes in the membrane structure on introducing up to 15 wt % modifier were evaluated by atomic force microscopy and density measurements. The microphase separation in modified polyphenylene oxide films was demonstrated. Introduction of graft copolyimide leads to an increase in the density of the hybrid films. The gas transport properties of the membranes were evaluated for H2, CO2, O2, O4, and N2. Introduction of up to 10 wt % modifier does not noticeably alter the permeability of the hybrid membranes to all the gases but increases the selectivity in gas separation.

Viscoplastic parameter identification of temperature‐dependent mechanical behavior of modified polyphenylene oxide polymers

Modified polyphenylene oxide (MPPO) is a widely known thermoplastic polymer and is extensively utilized for weight reduction of automobiles since it possesses outstanding mechanical properties, such as resistance and toughness. In this study, the viscoplastic behaviors of MPPO with respect to changes in temperature were identified through an approximate optimization method. For this work, parameter studies were conducted with a tensile simulation of the MPPO polymer, in accordance with the modified two‐layer viscoplastic material parameters and the suggested shift parameter. The sensitivity tendency of the force‐displacement curves was captured in accordance with the material parameters. Computational experiments for obtaining calibration error data were performed using the material parameters based on interior central composite design. Surrogate models of root mean square error relative to force and displacement were generated using the response surface method. The accuracy of the surrogate models was evaluated with R‐square. Optimization for obtaining the material parameters was performed using the non‐dominant sorting genetic algorithm‐II. The results showed that the calibration error from the finite element analysis was minimized and agreed with experimental data. POLYM. ENG. SCI., 59:E200–E211, 2019. © 2018 Society of Plastics Engineers

근사 최적 기법을 이용한 변성 폴리페닐렌 옥사이드 폴리머의 점소성 모델 보정 연구

근사 최적 기법을 이용한 변성 폴리페닐렌 옥사이드 폴리머의 점소성 모델 보정 연구

Safety assessment of the substance ground sunflower seed hulls, for use in food contact materials

This opinion of the EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF Panel) deals with the safety assessment of ground sunflower seed hulls, food contact material (FCM) substance No 1060, for use as an additive at up to 50% w/w in plastics such as polypropylene. The plastics are processed at up to 240°C and are intended for contact with dry foods only at room temperature or below. No migration data were provided for the additive as no migration is foreseeable. Concerning the possible presence and migration of impurities, as well as reaction and degradation products, a multistep investigation was used involving analysis of the plastic itself and then migration testing using modified polyphenylene oxide (MPPO) and test conditions of 10 days at 40 or 60°C. The highest migration, up to 54 mg/kg, was for the sum of four natural fatty acids. All other substances were either not detectable (< 30 μg/kg) or migrated at low concentrations only. For the additive itself, no genotoxicity data are required as it is a large polymer which will not be absorbed by the cells used in genotoxicity tests. The migration of natural fatty acids is not of toxicological concern. For the other substances found in the plastic, taking into account their nature and origin and given that migration was either not detectable or was low, they do not give rise to toxicological concern. The CEF Panel concluded that the substance ground sunflower seed hulls is not a safety concern for the consumer if used as an additive in plastics intended for contact with dry foods at room temperature or below. The seed hulls should be obtained from sunflower seeds that are fit for human consumption and the plastic containing the additive should be subjected to processing temperatures no higher than 240°C.

Isotope Internal Standard Method for Determination of Four Acrylamide Compounds in Food Contact Paper Products and Food Simulants by Ultra-High Performance Liquid Chromatography Tandem Mass Spectrometry

A new method was developed for the determination of four acrylamide compounds (acrylamide, methacrylamide, N-methylol acrylamide, N-(Methoxymethyl)methacrylamide) in food contact paper products, three kinds of water-based food simulants, and dry food simulant (modified polyphenylene oxide, MPPO) by using ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Acetonitrile was used as the extraction solvent for different kinds of samples. The extraction solution of paper products was purified with QuEChERS technology. Four analytes were separated by gradient elution in a UPLC HSS T3 column (100 mm × 2.1 mm, 1.8 μm) with methanol and 0.1 % formic acid water as mobile phases, and then detected in electrospray ionization mode of MS/MS with multiple reaction monitoring (MRM). Under the optimal conditions, the calibration curves for four analytes were linear within the range of 1.0–200 μg/L and the correlation coefficients were higher than 0.998. The quantitation limits of the method (S/N = 10) of four analytes were in the range of 0.3–20 μg/kg. The mean recoveries for five sample matrixes at three spiked concentration levels of 0.3–200 μg/kg were in the range of 81–108 % with the relative standard deviations (RSDs, n = 6) values ranging from 2.5 to 7.1 %. The developed method is accurate, simple and rapid, which can be applied to the determination of acrylamide compounds in food contact paper products and food simulants.

Migration of two antioxidants from packaging into a solid food and into Tenax®

The migration of chemicals from packaging materials into foods is an important issue in food safety and quality. European legislation sets specific migration limits which compliance must be assessed, surveyed and controlled by industry and authorities. Recently, the new Regulation UE 10/2011 included a new simulant - the Modified Polyphenylene Oxide (Tenax®) for solid dry foods. The objective of this work was to compare the migration kinetics of two antioxidants into Tenax® as compared to rice at 3 temperatures: 23, 40 and 70 °C. The application of two different solutions of the 2nd Fick's law to describe and simulate the migration of the migrants to the present systems was studied. Diffusion coefficients ranged between 4.80E-13 and 2.84E-11 cm2/s for the migration into Tenax® and between 6.90E-18 and 4.33E-17 cm2/s for the migration into rice. The partition coefficients ranged between 6 and 29 for Tenax® and were over 1000 for rice. The activation energy for the migration into rice was half of that for Tenax®. The models described relatively well the experimental data (ε < 12% and < 30% for rice and Tenax®, respectively). Results indicate that the food simulant tends to overestimate migration values and thus can be safely used to assess materials compliance when materials are intended to contact with rice. However, results also indicate that Tenax® is a much more severe simulant in representing rice.

Test procedures for obtaining representative extracts suitable for reliable in vitro toxicity assessment of paper and board intended for food contact

This paper describes the use of a suite of extraction procedures applicable to the assessment of the in vitro toxicity of paper/board samples intended for food-contact applications. The sample is extracted with ethanol, water, or exposed to modified polyphenylene oxide (Tenax®) for fatty, non-fatty and dry food applications, respectively. The water extracts are directly suitable for safety assessment using in vitro bioassays. The ethanol extracts of the paper/board and of the exposed Tenax require pre-concentration to give acceptable sensitivity. This is because the in vitro bioassays can tolerate only a small percentage of added organic solvent before the solvent itself inhibits. The extraction procedures have been selected such that they mimic the foreseeable conditions of use with foods and that they are also fully compatible with the battery of in vitro biological assays for the safety assessment of the total migrate. The application of the extraction protocols is illustrated by the results for one of the many paper/board samples provided by the BIOSAFEPAPER project industrial platform members. The assessment indicated that this sample should not be considered as suitable for use with fatty foodstuffs but was suitable for dry and non-fatty foods. Information subsequently received from the manufacturer revealed that this was a non-food-grade product included in the project to test the capabilities of the bioassay procedures. The selection criteria for the test conditions and the suite of methods developed have been prepared in Comité Européen de Normalisation (CEN) format and is currently being progressed by CEN/TC172 as a European Standard.

Migration of organic compounds from a multilayer plastic–paper material intended for food packaging

This paper deals with the study of the kinetic migration of a series of organic compounds representative of potential contaminants in packaging materials and used as surrogates (o-xylene, acetophenone, dodecane, naphthalene, 2,3,4-trichloroanisole, benzophenone, isomeric mix of diisopropylnaphthalene, diisobutyl phthalate and methyl stearate). Migration to one side of a solid simulant, Tenax, also referred to as MPPO (modified polyphenylene oxide), was investigated in this study. One spiked sample of multilayer material was used to optimise the extraction procedures for the multilayer paper-based material and the Tenax as well as to perform kinetic migration studies. Three sequential extractions using ethanol were necessary for the strips of the multilayer material but only one extraction was necessary for the solid simulant to obtain >70% recovery of the surrogates. These results enabled us to specify the extraction requirements of the multilayer sample and the solid simulant and as well as those of the migration tests at high temperature using Tenax as solid simulant. The matrix effect associated with the extraction of the contaminants from the multilayer sample is also discussed.

Studies on the Effect of Polyamide-6 onto Modified Polyphenylene Oxide Matrix in Presence of Fumaric Acid as a Compatibilizer

Polymer blends of modified polyphenylene oxide (mPPO) and polyamide-6 (PA-6) are immiscible and incompatible in nature. However fumaric acid (FA) is used as a compatibilizer for the compatibilizing of mPPO/PA-6 blend systems. During melt compounding functional groups of the polymer components were reacted in the presence of a compatibilizer in the extruder. The blends were characterized by using FTIR, SEM, and mechanical behavior testing. The concentration of FA compatibilizer varies inversely w.r.t. PA-6 concentration in the blend systems. However the blend composition of PA-6 (10%) shows good miscibility among the other blend systems under present study.

Flame retardancy and toughening of high impact polystyrene

AbstractFlame retardant high impact polystyrene (HIPS) was prepared by melt blending HIPS, nano‐modified aluminum trihydrate (nano‐CG‐ATH), red phosphorus masterbatch (RPM), and modified polyphenylene oxide (MPPO). Styrene‐butadiene‐styrene (SBS) was used as a toughener in this research. The effects of nano‐CG‐ATH, RPM, MPPO, and SBS on properties of HIPS composites were studied by combustion test, mechanical tests, and thermogravimetric analysis. The morphologies of fracture surfaces and char layers were characterized through scanning electron microscopy (SEM). The HIPS/nano‐CG‐ATH/RPM/MPPO (60/6/9/25) composite and its combustion residues at various temperatures were characterized by Fourier transform infrared (FTIR) spectra analysis. The results showed that the UL‐94 rating of the HIPS/nano‐CG‐ATH/RPM/MPPO (60/6/9/25) composite reached V‐0 and its char layer after flame test was integrated, but its impact strength was low. Addition of SBS improved its impact property and did not influence its thermal and flame retardant properties but lowered its tensile strength and flexural modulus to some extent. The FTIR spectra confirmed that the POC group was present in the charred substance. POLYM. COMPOS., 28:551–559, 2007. © 2007 Society of Plastics Engineers

Migration of dehydroabietic and abietic acids from paper and paperboard food packaging into food-simulating solvents and Tenax TA

An investigation was undertaken to establish the concentration in paper products of dehydroabietic (DHA) and abietic (AA) resin acids, present in rosin, which are major toxicants of pulp- and paper-mill effluent. Their migration was studied from paper and paperboard products into various food-simulating solvents and the substitute fatty food simulant Tenax TA (modified polyphenylene oxide). DHA and AA were detected in five of 10 virgin paper products and in all 10 recycled paperboard products for food-contact use at concentrations of 14–500 and 110–1200 µg/g, respectively. In virgin paper products, the highest migration was into 95% ethanol or heptane, with negligible or no migration into other solvents. In recycled paperboard products, migration was highest into 95% ethanol, but was also observed into 20% ethanol, water and heptane. Migration to Tenax TA was also observed and the migration level increased with time. The maximum migration levels of DHA and AA into food simulants were 0.853 and 3.14 µg/g, respectively. The results suggest that, in the worst case, the daily intake of DHA and AA from paper and paperboard products was 50 times lower than the tolerable daily intake of rosin.

Prediction for debonding damage process and effective elastic properties of glass-bead-filled modified polyphenylene oxide

A three-dimensional three-phase finite element unit cell model has been applied to predict the debonding damage process of particulate polymer composites (PPC) during tensile deformation. The model consists of a particle, an interface and a polymer matrix. The particle-matrix debonding process has been simulated by using a particle-matrix debonding criterion and a vanishing finite element technique. For verification of the predicted results, the results obtained in the in situ SEM experiments of our previous study on glass beads reinforced modified polyphenylene oxide (GB/PPO) were used The predicted results are in good agreement with the experimental micro-scale tensile debonding-damage process. Anisotropic damage in materials like PPC is very difficult to measure by conventional experimental methods. In order to provide anisotropic damage information of the damaged composites, this was amongst the first time to predict the effective elastic properties of PPC in different principal directions by performing a virtual load–unload test on the partially debonded cell model. Some predicted results would be compared with those of experimental load–unload test.