The terahertz (THz) spectroscopy of paramylon (β-1,3-glucan) and paramylon-ester extracted from microalgae called as Euglena have been studied by Fourier Transform Infrared Spectrometer (FT-IR) in a frequency range from 0.3 to 9 THz. The absorption spectra of paramylon were analyzed by comparing them with cellulose that has a similar long-chain -(C6H10O5)n-structure with paramylon. The differences in absorption features between paramylon and cellulose may be caused by their different chain structures. The broad absorption spectra of paramylon-ester can be attributed to some sort of disorder of long-chain molecular vibration modes due to the substitution of propionyl chloride and long-chain acid chloride by esterification.

The terahertz (THz) spectroscopy of paramylon ($\beta$-1,3-glucan) and paramylon ester extracted from Euglena have been studied by Fourier Transform Infrared Spectrometer (FT-IR) in a frequency range from 0.3 to 10 THz. The absorption spectra of paramylon were analyzed by comparing with cellulose that has a similar long-chain -(C6 H10O5)n-structure. The broad absorption spectra of paramylon can be attributed to some sort of disorder of long chain molecular vibration modes due to the interactions.

We have developed high-performance biomass-based plastics that consist of poly(lactic acid) (PLA) and kenaf fiber, which fixates CO2 efficiently. Adding this fiber to PLA greatly increases its heat resistance (distortion temperature under load) and modulus and also enhances its crystallization, so the ease of molding this material is improved. Eliminating the short particles from the kenaf fiber improves its effect on the impact strength. Kenaf fiber without the particles exhibits effects on these characteristics of PLA practically comparable to the effects of glass fiber. Furthermore, adding a flexibilizer (a copolymer of lactic acid and aliphatic Polyester) to the composites improves their strength. These composites (PLA/kenaf fiber and PLA/ kenaf fiber/ flexibilizer) show good practical characteristics for housing materials of electronic products in comparison with petroleum-based plastics used in housing such as glassfiber-reinforced acrylonitrile-butadien-styrene (ABS) resin. (c) 2006 Wiley Periodicals, Inc.

We have developed high-performance biomass-based plastics consisting of polylactic acid (PLA) and fiber of kenaf, which fixates CO2 efficiently. Adding this fiber to PLA greatly improves the heat resistance, i.e., distortion temperature under load, and modulus. It also promotes PLA crystallization, improving its molding characteristic. Eliminating short particles from the kenaf fiber improves the impact strength of the composite, making the characteristics of kenaf fiber reinforced PLA practically comparable to those of glass fiber-reinforced PLA. Adding a flexibilizer (a copolymer of lactic acid and aliphatic polyester) to the composite further improves its strength. Elimination of water-soluble materials, such as water-soluble pectin, from the kenaf fiber improved the coloring characteristic of the composite. The composites (PLA/kenaf and PLA/kenaf/flexibilizer) show good characteristics as housing materials for electronic products, superior to those of a glass fiber-rein forced petroleum-based ABS resin currently used in housing.

We describe an intelligent biomass-plastic with a rewritable shape memory. First, we synthesized the network structure by cross-linking a polylactic acid (PLA) derivative with a diisocyanate linker. This structure performed much better as a shape memory than the inherent crystal domain. Then, we introduced the furan and maleimide functional groups, which form a thermo-reversible bonding based on Diels-Alder reaction, into the molecular structure of the PLA derivative. This bond works like a thermo-switch, providing two normally incompatible characteristics, namely shape memory and recyclability (rewritability). Currently, shape-memory plastics with cross-linked structures are not rewritable. When the thermo-switch is on at low temperatures, the bio-plastic 'memorizes' its original shape and can completely recover from a deformed shape. When the switch is turned off at high temperatures, the memory is erased and the plastic becomes rewritable.

We have developed self-extinguishing epoxy-resin compounds that contain no environmentally hazardous flame retardants such as halogen or phosphorous derivatives, and used them to develop glass epoxy laminates for printed wiring boards (PWBs). The new epoxy-resin compounds, which mainly consist of phenol-aralkyl-type epoxy resins and hardeners, formed stable foam layers that retarded heat transfer, and thus were self-extinguishing. A laminate consisting of one of the new epoxy-resin compounds with safe metal hydroxides, which absorb heat during combustion, showed high flame retardancy. We achieved excellent flame retardancy (UL94V-0) of the new laminate by adding far less aluminum hydroxide (less than 50% by weight) than in laminates containing conventional epoxy-resin compounds. Especially beneficial is the fact that the new laminate with the hydroxide exhibits good practicality and can withstand the higher temperature required for lead-free soldering. Furthermore, the laminate can be safely disposed of by incineration or reclamation, and it can also be thermally recycled.

The flame retardancy and heat resistance of a phenolbiphenylene-type epoxy resin compound, which forms a self-extinguishing network structure, were increased by the inclusion of a benzoguanamine-modified phenol biphenylene resin. The benzoguanamine-modified phenol biphenylene resin contains a benzoguanamine unit to release non-flammable nitrogen substances during ignition and to increase the resin's reactivity toward epoxy resins, and biphenylene units to keep the resin's thermal degradation and water resistance. The addition of the benzoguanamine-modified phenol biphenylene resin in the epoxy resin compound improved the epoxy resin compound's flame retardancy and heat resistance, and also increased its glass transition temperature while maintaining its water resistance and mechanical properties. Copyright (C) 2003 John Wiley Sons, Ltd.

New flame-retardant epoxy resin compounds containing novolac derivatives with specific aromatic compounds have been developed. After crosslinking reactions between epoxy resin and hardener, the epoxy resin compounds formed highly flame-retardant network structures that were obtained by including biphenylene and phenylene moieties in the main chains of novolactype epoxy resin and phenol novolac resin hardener. The high flame retardancy is due mainly to the stable foam layers that form during combustion because of the low elasticity at high temperatures and the high pyrolysis resistance of the compounds. Furthermore, the addition of excess phenol derivative hardener not only facilitates the formation of the foam layers by decreasing the crosslink densities but also reduces the amount Of flammable substances generated from the epoxy resin compounds during combustion. The use of a multifunctional epoxy resin containing four glycidyloxy groups in the compounds improved characteristics such as heat resistance and strength at high temperatures, while maintaining excellent flame retardancy. Copyright (C) 2001 John Wiley & Sons, Ltd.

A new, environmentally friendly, self-extinguishing epoxy-resin compound with no flame-retardants (such as halogen derivatives) has been developed for integrated circuit (IC) packaging. This compound mainly consists of phenol-aralkyl-type epoxy resin and hardener, both of which contain a multi-aromatic substituent, fused silica powder, and additives. The compound has a high flame retardancy resulting from the formation of a stable foam layer, which retards heat transfer, on the surface of the resin compound during combustion. Furthermore, the compound shows other excellent characteristics as a molding compound for IC packages. In fact, its packaging-reliability characteristics, those including resistance to humidity, soldering heat, and the effects of high-temperature storage, are better than those of current molding compounds used for large-scale integration (LSI) packaging. The new molding compound has thus already been applied to IC packages such as ball grid arrays (BGAs).

Flame-retardant plastics containing no toxic flame-retarding additives such as halogen (bromine) compounds and phosphorus compounds have been developed for electronic products. A polycarbonate (PC) resin containing a silicone derivative as a new safer flame-retarding aromatic has been developed for use in housings. A special silicone with a branched chain structure and with an aromatic group in the chain was found to be greatly effective in retarding the combustion of PC resin. The PC resin containing the silicone shows other good properties, such as strength, moldability and heat resistance as well as high flame retardance and also good recyclability. Moreover, the authors have developed a new flame-retardant epoxy resin compound containing no flame-retarding additives as a molding resin for electronic parts. A self-extinguishing network structure of the epoxy resin compound was obtained by using an aromatic epoxy resin and a phenol derivative hardener; both of which have multi-aromatic groups in their main chain. The high flame retardance was achieved by the formation of a foam layer during combustion. The epoxy resin compound has other good properties (resistance to humidity, solder heating and thermal cycles, etc.) as well as high flame retardance and can be used as a high quality molding resin for LSIs

Pyrolysis-based technology for the epoxy resin compounds (molding resin) used for molding electronic components has been studied for the purpose of recovering useful materials and reusing them. The molding resin contains silica filler (70-85% by weight) and flame retardant consisting of bromine compounds and antimony oxides. This study has clarified those pyrolysis conditions best suited to reduction of the impurities (carbon, antimony, and ionic substances) in the recovered silica tiller This has contributed to the development of a practical pyrolysis technology in which a roller kiln-type furnace is used to recover high-purity silica filler. The recovered silica was sufficiently pure to be employed as an inorganic tiller in epoxy resin compounds to be used as cast-insulating materials and original molding resins. The combustion exhaust gas generated in the pyrolysis of the molding resin has been successfully treated by a secondary combustion method that decomposed organic bromine compounds in the gas to a safe level, and it converted antimony bromides to antimony oxides, which could then be collected by a dry recovery process at a useful purity.

An environmentally conscious polycarbonate (PC) resin containing a silicone derivative as a new flame retardant that generates no toxic gas has been developed for use in electronics products. A special silicone with a branched chain structure and with aromatic group in the chain was found to be greatly effective in retarding the combustion of PC resin and its derivatives. This silicone derivative has shown itself to be a perfect replacement for halogen compounds, which become a potential environmental hazard when the materials are subjected to combustion. Further, the PC resin containing the silicone derivative shows other good properties, such as strength, moldability, and heat resistance as well as high flame retardance; its impact strength is in much better than that of PC resins containing bromine compounds as their flame retardants.

An environmentally conscious polycarbonate (PC) resin containing a silicone derivative as a new flame retardant that generates no toxic gas has been developed for use in electronics products. A special silicone with a branched chain structure and with aromatic group in the chain was found to be greatly effective in retarding the combustion of PC resin and its derivatives. This silicone derivative has shown itself to be a perfect replacement for halogen compounds, which become a potential environmental hazard when the materials are subjected to combustion. Further, the PC resin containing the silicone derivative shows other good properties, such as strength, moldability, and heat resistance as well as high flame retardance; its impact strength is in fact much better than that of PC resins containing bromine compounds as their flame retardants.

A practical recycling system has been developed for Printed Wiring Boards (PWBs) with electronic parts mounted on them. This system consists of part-removing, solder-removing and resin-board pulverizing/separating processes, and recovers useful materials effectively. For the part removal, we developed two types of part-removal apparatuses. One of these successfully removes through-hole devices as well as surface mounted devices from PWBs with almost no damage by heating and impacting the PWBs. The other can effectively remove all parts as crushed by using shear force provided with shearing rollers. Most of the solder is also removed in the part-removal process by heating and impacting, while that remaining on the resin board surface can effectively be removed later by surface abrading followed by heating/impacting. After the removal of the parts by heating/impacting and of the solder, the resin-boards are pulverized and then the resulting materials are separated into a copper-rich powder and a powder consisting of glass fiber and resin (GR powder). The parts (including gold) recovered by using these removal apparatuses are valuable metal resources for refining, while the parts removed by using heat-impact type apparatus have a strong potential to be reused for their original purpose after being checked for reliability. The copper-rich powder is also a copper resource for refining. The GR powder is usable as a filler for polymer products.

A practical recycling system has been developed for printed wiring boards (PWBs) with electronic parts mounted on them. This system consists of part-removing, solder-removing, and resin-board pulverizing/separating processes, and is effective in the recovery of useful materials. We have developed a part-removal apparatus which successfully removes through-hole devices as well as surface mounted devices from PWBs with almost no damage to the devices themselves. Most of the solder is removed by the part-removal, and later by surface abrasion followed by heat/impact. After the removal of parts and solder, the resin-boards are pulverized, and the resulting powder is then separated into two types: a copper-rich powder and a powder which consists of glass fiber and resin (GR powder). The copper-rich powder is a good copper resource for refining; the GR powder is usable as a filler for polymer products. Recovered parts which contains valuable metal resources (including gold), can be refined out, as is most commonly the case in other recycling systems, but a more economic and ecologically sound approach would be to exploit the potential of parts removed in this system to be reused for their original purposes after being checked for reliability.

This paper describes a pyrolysis-based technology for recovering useful materials from molding resin waste, which is the main type of thermosetting plastic waste generated in the fabrication of IC packages. In our pyrolysis of molding resin waste, the main impurities in the recovered silica were carbon (C), antimony (Sb) and phosphoric acid ion (PO43). The amount of carbon and phosphoric acid ion decreased with increased heating temperature and oxygen concentration. However, the antimony remained constantly between 400 and 1000°C because diantimony tetraoxide (Sb2O4), which is hard to volatilize, was formed by oxidation. Our experimental results suggest that the most effective way to reduce the impurities is to heat at between 1000-1100°C and to keep oxygen concentration at about 8 vol%. On the basis of these results, we used a roller kiln type furnace as a prototype practical pyrolysis system for recovering high purity silica. The purity achieved was as follows: C<100 ppm, Sb<1000 ppm, and PO43<20 ppm, pure enough to be used as inorganic filler for cast insulating materials. The combustion exhaust gas generated by pyrolysis of the molding resin waste was decomposed by a secondary combustion method which was found to decrease organic brominated substances to a sufficiently safe level, and also, to convert the antimony tribromide to diantimony trioxide, which can be collected by a dry recovery process at a high recovery rate and at a useful purity

Reported here is a study for recycling of residue of molding resin for IC packages (molding resin waste). Molding resin waste pulverized into a powder showed good surface reactivity almost comparable to that of silica powder. When the waste powder of low-stress type molding resin was recycled into standard type molding resin, the thermal resistance of the resulting product was superior to that of the standard molding resin. Moreover, the waste powder of molding resin was found to be useful as a general filler for resin type construction materials, paints and adhesives, and as a decorating agent for construction materials

This paper describes the recycling of the mold waste from printed wiring boards (PWBs) and the molding resin used for IC packages, which are the main types of thermosetting plastic waste produced in the electronic component production processes. A practical process for pulverizing the PWB waste and separating the resulting powder into a copper rich powder and a powder consisting of glassfiber and resin (glassfiber-resin powder) was developed. Using this process, up to 94% of the copper was recovered from a pulverized PWB of 100-300 μm average particle size. The recovered glassfiber-resin powder was found to be more useful than either talc, calcium carbonate or silica at improving the mechanical strength and the thermal expansion properties of polymer products, such as paints and adhesives. The molding resin powder showed good surface reactivity, comparable to that of a silica powder surface. In recycling the molding resin powder to the original molding resin, recycling of the waste powder of the low stress type molding resin to standard mold resin was especially effective in improving the humidity penetration and the thermal impact resistance of the original standard resin. Moreover, the molding resin powder could be used as a general filler for resin type construction materials, and as a decorating agent for improving the surface hardness of construction materials