Masahiro Funabashi

Chemical Synthesis of Fully Biomass-Based Poly(butylene succinate) from Inedible-Biomass-Based Furfural and Evaluation of Its Biomass Carbon Ratio

We have produced fully biomass-based poly(butylene succinate) (PBS) from furfural produced from inedible agricultural cellulosic waste. Furfural was oxidized to give fumaric acid. Fumaric acid was hydrogenated under high pressure with a palladium-rhenium/carbon catalyst to give 1,4-butanediol, and with a palladium/carbon catalyst to give succinic acid. Dimethyl succinate was synthesized from fumaric acid by esterification and hydrogenation under normal pressure. Fully biomass-based PBS was obtained by polycondensation of biomass-based 1,4-butanediol and biomass-based succinic acid or dimethyl succinate. The biomass carbon ratio calculated from (14)C concentrations measured by accelerator mass spectroscopy (AMS) verified that the PBS obtained in this study contained only biomass carbon. The polycondensation of biomass-based 1,4-butanediol and petroleum-based terephthalic acid or dimethyl terephthalate gave partially biomass-based poly(butylene terephthalate), which is an engineering plastic.

Anaerobic Biodegradation Tests of Poly(lactic acid) under Mesophilic and Thermophilic Conditions Using a New Evaluation System for Methane Fermentation in Anaerobic Sludge

Anaerobic biodegradation tests of poly(lactic acid) (PLA) powder were done at the thermophilic (55 °C) and mesophilic temperature (35 °C) under aquatic conditions [total solid concentrations of the used sludge were 2.07% (at 55 °C) and 2.24% (at 35 °C)] using a newly developed evaluation system. With this system, the evolved biogas is collected in a gas sampling bag at atmospheric pressure. This method is more convenient than using a pressure transducer or inverted graduated cylinder submerged in water. PLA was degraded about 60% in 30 days, about 80% in 40 days and about 90% in 60 days at 55 °C. On the other hand, the PLA degradation started in 55 days at 35 °C and degradation rate was much slower than at 55 °C.

Biodegradability Evaluation of Polymers by ISO 14855-2

Biodegradabilities of polymers and their composites in a controlled compost were described. Polycaprolactone (PCL) and poly(lactic acid) (PLA) were employed as biodegradable polymers. Biodegradabilities of PCL and PLA samples in a controlled compost were measured using a Microbial Oxidative Degradation Analyzer (MODA) according to ISO 14855-2. Sample preparation method for biodegradation test according to ISO/DIS 10210 was also described. Effects of sizes and shapes of samples on biodegradability were studied. Reproducibility of biodegradation test of ISO 14855-2 by MODA was confirmed. Validity of sample preparation method for polymer pellets, polymer film, and polymer products of ISO/DIS 10210 for ISO 14855-2 was confirmed.

Biodegradation of Poly(butylene succinate) Powder in a Controlled Compost at 58 °C Evaluated by Naturally-Occurring Carbon 14 Amounts in Evolved CO2 Based on the ISO 14855-2 Method

The biodegradabilities of poly(butylene succinate) (PBS) powders in a controlled compost at 58 °C have been studied using a Microbial Oxidative Degradation Analyzer (MODA) based on the ISO 14855-2 method, entitled “Determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions—Method by analysis of evolved carbon dioxide—Part 2: Gravimetric measurement of carbon dioxide evolved in a laboratory-scale test”. The evolved CO2 was trapped by an additional aqueous Ba(OH)2 solution. The trapped BaCO3 was transformed into graphite via a serial vaporization and reduction reaction using a gas-tight tube and vacuum manifold system. This graphite was analyzed by accelerated mass spectrometry (AMS) to determine the percent modern carbon [pMC (sample)] based on the 14C radiocarbon concentration. By using the theory that pMC (sample) was the sum of the pMC (compost) (109.87%) and pMC (PBS) (0%) as the respective ratio in the determined period, the CO2 (respiration) was calculated from only one reaction vessel. It was found that the biodegradabilities determined by the CO2 amount from PBS in the sample vessel were about 30% lower than those based on the ISO method. These differences between the ISO and AMS methods are caused by the fact that part of the carbons from PBS are changed into metabolites by the microorganisms in the compost, and not changed into CO2.

Composites consisting of poly(ε-caprolactone) and cellulose fibers directly molded during polymerization by yttrium triflate

Composite samples consisting of poly(e-caprolactone) (PCL) and cellulose fibers (CF) were prepared by the direct molding method during polymerization from e-caprolactone (CL) monomers. CL liquid was mixed with yttrium triflate as a catalyst and 2-propanol as an initiator. CF was easily added to CL liquid and was homogeneously mixed with CL liquid by this method. The mixture was put into a plastic tube. Heating temperature varied from 60 to 120 °C and heating time varied from 6 to 48 h. CF content varied from 0 to 30 wt%. After cooling, the sample was removed from the tube and cut into a column shaped specimen. PCL composites with CF dispersed homogeneously were obtained. The mechanical properties such as elastic modulus and strength of these PCL composites with CF were measured by compression test using the above specimen. The maximum values of modulus and strength of composite samples are the maximum values 654 and 13 MPa, when fiber content was 34% and these values are greater than those of PCL samples without CF. The biodegradability of PCL composites in an aqueous medium with commercial compost was evaluated measuring the biochemical oxygen demand (BOD). The biodegradability of composite samples was not affected by the presence of CF.

Quick Preparation of Moisture-Saturated Carbon Fiber-Reinforced Plastics and Their Accelerated Ageing Tests Using Heat and Moisture

A quick method involving the control of heat and water vapor pressure for preparing moisture-saturated carbon fiber-reinforced plastics (CFRP, 8 unidirectional prepreg layers, 1.5 mm thickness, epoxy resin) has been developed. The moisture-saturated CFRP sample was obtained at 120 °C and 0.2 MPa water vapor in 72 h by this method using a sterilizer (autoclave). The bending strength and viscoelastic properties measured by a dynamic mechanical analysis (DMA) remained unchanged during repetitive saturation and drying steps. No degradation and molecular structural change occurred. Furthermore an accelerated ageing test with two ageing factors, i.e., heat and moisture was developed and performed at 140–160 °C and 0.36–0.62 MPa water vapor pressure by using a sealed pressure-proof stainless steel vessel (autoclave). The bending strength of the sample decreased from 1107 to 319 MPa at 160 °C and 0.63 MPa water vapor pressure in 9 days. Degraded samples were analyzed by DMA. The degree of degradation for samples was analyzed by DMA. CFRP and degraded CFRP samples were analyzed by using a surface and interfacial cutting analysis system (SAICAS) and an electron probe micro-analyzer (EPMA) equipped in a scanning electron microscope.

Highly Accelerated Aging Method for Poly(ethylene terephthalate) Film Using Xenon Lamp with Heating System

PET films were degraded at temperature higher than 100°C with steam and xenon light by using the newly developed system. Degradation products obtained using the proposed and conventional systems were essentially the same, as indicated by the similar increase in the intensity of the carbonyl peak near 1685 cm−1 in the FT-IR spectra of irradiated specimens and spectrum of original PET film. Elastic moduli derived from the stress-strain (SS) curves obtained in tensile tests were almost the same in the case of the proposed and conventional systems and were independent of the heating temperature, light intensity, and irradiation time. Tensile strength of degraded PET films decreases with increasing heating temperature. Tensile strengths of PET films degraded at same temperature decrease linearly with increasing intensity of xenon light. The lifetime at 90% strength of PET films was calculated. Attempts were made to express this lifetime as functions of the light intensity and the reciprocal of the absolute temperature by using the Eyring model. Estimated lifetime 15.9 h of tensile test using Eyring model for PET film agreed with the lifetime 22.7 h derived from data measured using the xenon weather meter.

Biobased carbon content of resin extracted from polyethylene composite by carbon-14 concentration measurements using accelerator mass spectrometry

An estimation procedure for biobased carbon content of polyethylene composite was studied using carbon-14 (14C) concentration ratios as measured by accelerated mass spectrometry (AMS). Prior to the measurement, additives and fillers in composites should be removed because they often contain a large amount of biobased carbon and may shift the estimation. Samples of resin with purity suitable for measurement were isolated from composites with a Soxhlet extractor using heated cyclohexanone. After cooling of extraction solutions, the resin was recovered as a fine semi-crystalline precipitate, which was easily filtered. Recovery rates were almost identical (99%), even for low-density polyethylene and linear low-density polyethylene, which may have lower crystallinity. This procedure could provide a suitable approach for estimation of biobased carbon content by AMS on the basis of the standard ASTM D 6866. The biobased carbon content for resin extracted from polyethylene composites allow for the calculation of biosynthetic polymer content, which is an indicator of mass percentage of the biobased plastic resin in the composite.

Mechanical and Thermal Properties of Composites of Epoxy Resin Derived from Kraft Lignin Filled with Cellulose Particles

A mixture of ester-carboxylic acid derivatives (KL polyacid, KLP A) was obtained by reaction of an ethylene glycol solution of Kraft lignin (KL) and succinic anhydride in the presence of a catalytic amount of dimethylbenzylamine at 100 °C. Cellulose particles were added to the above mixture with various mixing ratios from 0 to 60 wt%. A prepolymer of lignin-based epoxy resin was prepared by a reaction of the mixture of KLP A and cellulose particles with ethylene glycol diglycidyl ether (EGDGE) at 100 °C. The above mixtures were molded into sheets at 130 °C for 5 hours. The mechanical properties of the samples were investigated by tensile tests using plate type specimens. The elastic modulus and tensile strength were determined by the tensile tests. Thermal properties of composite samples were measured by differential scanning calorimetry (DSC) and thermogravimetry (TG). Glass transition temperatures of samples were determined by DSC. Thermal decomposition temperatures and mass residues were determined by TG. The values of strength and modulus determined by tensile tests were maximum at cellulose content of 60 wt% for composite samples with cellulose particles of 25 mm diameter. Thermal properties such as peak temperatures of thermal decomposition and glass transition temperature determined by TG and DSC were not affected by cellulose contents.

Poly(lactic acid) Composites Directly Molded from Lactide and Particle Fillers

Polymer composite samples consisting of L-Lactic acid (LA) was reacted by ring-opening polymerization with aluminum triflate as a catalyst, glycerol as an initiator and various particles as fillers. Cellulose particles, kaolin and silica gel with different particle sizes were employed as fillers. Filler content was varied 0 to 100 wt% as ratio of filler weight to PLA weight. L-Lactide (L-LA), aluminum triflate as catalyst, glycerol as an initiator and particles were mixed at room temperature and then were put into plastic tubes. The mixture in tubes was heated and reacted at 100 oC for 6 hours. The samples were removed from tubes after cooling and were cut into the column shape specimen with diameter of 10 mm and ca. 10 mm height. By the above procedure, particles could be mixed to poly(lactic acid) (PLA) matrix easily and homogeneously. The molecular weight and molecular weight distribution of PLA matrix were determined by gel permeation chromatography (GPC). Apparent density of composite samples was calculated by using weight and sizes of column shape specimens. The mechanical properties such as elastic modulus and strength were investigated by compression tests using column shape specimens. Molecular weight and molecular weight distribution were almost constant for all the samples with and without particles. Elastic modulus and compression strength were improved by particles. For the cellulose particles filled samples, the highest values of elastic modulus and compression strength were derived at filler content of around 20 vol%. The influences of sizes and types of particles on the physical properties such as molecular weight, density and mechanical properties were investigated.