マテリアルライフ
Online ISSN : 2185-7024
Print ISSN : 0915-3594
ISSN-L : 0915-3594
4 巻, 1 号
選択された号の論文の4件中1~4を表示しています
  • 成澤 郁夫
    1992 年4 巻1 号 p. 9-16
    発行日: 1992/01/25
    公開日: 2011/04/19
    ジャーナル フリー
  • Peter P. Klemchuk
    1992 年4 巻1 号 p. 17-36
    発行日: 1992/01/25
    公開日: 2011/04/19
    ジャーナル フリー
    Increasing volumes of municipal solid waste (MSW) and decreasing means of disposal are creating a serious problem in the United States. Plastic waste has been identified as a major issue even though it is still only a small portion of the total volume of MSW. In part, that is because of the relatively low rates of environmetal degradation of most plastics; in part, because plastics litter is highly visible and long lasting; in part, because forecasts predict plastics will be an even larger component of MSW in the future. The plastics and solid waste problem is receiving much attention in the United States. Several approaches to solid waste disposal are being investigated, including source reduction, recycling, composting, degradable plastics, incineration, and sanitary landfills. All are being studied intensively to overcome the serious disposal problems associated with increasing amounts of MSW. The results to date, and especially the directions being taken, are encouraging. They indicate solid waste will be disposed by multiple means and the solid waste disposal practices of the near future will be much different from those of the present time.
    Degradable plastics were viewed only 1-2 years ago as an exciting new approach to help solve the solid waste problem. However, the finding that sanitary landfills are sterile environments where little degradation takes place has reduced the attraction of degradable plastics. Their attraction has been reduced also by the realization that, although packaging plastics can be made photodegradable, they are not biodegradable - their high molecular weights and structures prevent complete breakdown by organisms in reasonable time periods. Some of the former luster of degradable plastics has been tarnished because several environmental groups have been critical of attempts to take advantage of the public's considerable interest in degradable plastics to sell products which do not meet marketing claims. As a result of all these developments, interest in degradable plastics is low at this time. Other means of solving the problem, notably source reduction, recycling, composting and incineration are more likely to be adopted. Degradable plastics are not likely to play a major role as solutions to the solid waste problem.
  • 伊藤 政幸, 池島 義昭, 白石 忠男, 佐藤 隆一, 田中 勲, 市橋 芳徳
    1992 年4 巻1 号 p. 37-43
    発行日: 1992/01/25
    公開日: 2011/04/19
    ジャーナル フリー
    研究用原子炉圧力容器とその本体の上から下へ貫通している実験用の配管との間に3個のシリコーンゴム製のOリングが装着されて13年間使用された.この間にOリングに加えられた諸因子を計算によって求めた結果, 放射線は最も高い位置で3.46kGy, 熱は原子炉運転時には50℃であり, 摺動は比較的少ないことが明らかになった, 同じ使用状態での余寿命を推定するために, 70℃で50kGy/hの線量率で同じ材質のOリングを線量を変えて時間加速照射を行い, 試料の機械的性質の変化を実機試料と比較した.その結果, 実機試料と同程度の劣化を時間加速試験試料に与えるためには前者より一桁以上高い線量が必要なことが判明した.
    得られた物性値を総合的に検討し, 破断伸びが50%に低下するまで使用可能と判断し, 同じ使用環境での余寿命を26年と推定した.
  • 石原 由美子, 池村 糺, 武末 知行, 黒木 健
    1992 年4 巻1 号 p. 44-49
    発行日: 1992/01/25
    公開日: 2011/04/19
    ジャーナル フリー
    廃ポリエチレン (廃PE) のゼオライト触媒存在下での接触分解反応を行なった.その結果, 酸化劣化により主鎖に多量の>C=O, >C=C<を生成した廃PEは触媒存在下でより容易に橋かけおよび分子量増加ポリマー成分を生成した.廃PBは特異な付加重合反応を引き起こすことが見出された.これらの結果は廃PEを用いた架橋PE前駆体の合成, 分子量増加PEの回収など, 廃PEの分解低分子化による燃料化とは異なる方向での再資源化 (リサイクリング) の可能性を示す。
feedback
Top