Polymer Photochemistry最新文献_第9页

Studies of the development of scintillation characteristics of plastic scintillators during manufacture 塑料闪烁体在制造过程中闪烁特性发展的研究

Polymer Photochemistry Pub Date : 1984-01-01 DOI: 10.1016/0144-2880(84)90033-2

D.J.S. Birch, R.E. Imhof, K. Davidson, I. Soutar

引用次数: 0

Photostabilising action of Ni(II) bis(1-phenyl-3-methyl-4-decanoyl-5-pyrazolate), sanduvor NPU, in a polypropylene matrix 镍(II)二(1-苯基-3-甲基-4-癸醇-5-吡唑酸酯)在聚丙烯基体中的光稳定作用

Polymer Photochemistry Pub Date : 1984-01-01 DOI: 10.1016/0144-2880(84)90041-1

Norman S. Allen , Alfonso Chirinos-Padron , John H. Appleyard

{"title":"Photostabilising action of Ni(II) bis(1-phenyl-3-methyl-4-decanoyl-5-pyrazolate), sanduvor NPU, in a polypropylene matrix","authors":"Norman S. Allen , Alfonso Chirinos-Padron , John H. Appleyard","doi":"10.1016/0144-2880(84)90041-1","DOIUrl":"10.1016/0144-2880(84)90041-1","url":null,"abstract":"<div>The photostabilising action of the metal chelate nickel(II) bis(1-phenyl-3-methyl-4-decanoyl-5-pyrazolate) in polypropylene is examined using normal and second-order derivative ultraviolet, infrared and phosphorescence spectroscopic techniques and hydroperoxide analysis. Although the chelate quenched the phosphorescence emission of a powerful sensitiser, benzophenone, there was no photoprotective action when the samples containing the chelate and the sensitiser were irradiated. In the case of anthraquinone there was no quenching and no photoprotection. Processing history plays a major role in controlling the photostabilising performance of the chelate. The effect of photosensitised oxidation with 365 nm light is examined. While the initial hydroperoxide concentration appears to control the onset of carbonyl growth in the polymer, the rate of photodecomposition of the chelate shows no dependence on hydroperoxide concentration. Furthermore, the rates of photooxidation under polychromatic irradiation follow the same trends as those obtained under monochromatic irradiation. The results are explained in terms of hydroperoxide inhibition during processing, stabiliser consumption during photooxidation and macroalkyl radical (P·) scavenging.</div>","PeriodicalId":101036,"journal":{"name":"Polymer Photochemistry","volume":"5 1","pages":"Pages 333-349"},"PeriodicalIF":0.0,"publicationDate":"1984-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0144-2880(84)90041-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82290906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Primary photochemical processes in UV-irradiated poly(vinyl chloride) and chlorinated PVC 紫外线辐照聚氯乙烯和氯化聚氯乙烯的初级光化学过程

Polymer Photochemistry Pub Date : 1984-01-01 DOI: 10.1016/0144-2880(84)90037-X

C. Decker, M. Balandier

引用次数: 9

Contents of volume 4 第四卷内容

Polymer Photochemistry Pub Date : 1984-01-01 DOI: 10.1016/0144-2880(84)90059-9

引用次数: 0

Photodegradation of 1-naphthyl methacrylate-butyl methacrylate copolymers in benzene solution. III. Comparison with the thermal and radiation-induced degradations 1-甲基丙烯酸萘酯-甲基丙烯酸丁酯共聚物在苯溶液中的光降解3与热降解和辐射降解的比较

Polymer Photochemistry Pub Date : 1984-01-01 DOI: 10.1016/0144-2880(84)90035-6

S. Nishimoto, K. Yamamoto, T. Kagiya

{"title":"Photodegradation of 1-naphthyl methacrylate-butyl methacrylate copolymers in benzene solution. III. Comparison with the thermal and radiation-induced degradations","authors":"S. Nishimoto, K. Yamamoto, T. Kagiya","doi":"10.1016/0144-2880(84)90035-6","DOIUrl":"10.1016/0144-2880(84)90035-6","url":null,"abstract":"<div>Photodegradation characteristics of 1-naphthyl methacrylate (1NMA) homopolymer and 17·1 mol% 1NMA-containing copolymer with butyl methacrylate (BMA) were compared with their thermal and γ-ray-induced degradation behaviour. The TG-DSC analyses under N2 showed that both the poly(1NMA) and poly(1NMA-co-BMA) powders degrade at 300–400°C. Heating of the copolymer up to 380°C under deaerated conditions produced 1NMA and BMA monomers. These polymers underwent main-chain scission simultaneously with a Fries rearrangement of the pendant 1-naphthyl ether groups by γ-radiolysis of the deaerated benzene solutions. The G-value of the main-chain scission was evaluated as 0·14 independent of the 1NMA content. The <math><mtext>M</mtext><msub><mi></mi><mn>w</mn></msub><mtext>M</mtext><msub><mi></mi><mn>n</mn></msub></math> ratio decreased and approached 2·0 asymptotically upon increasing the irradiation dose. On photoirradiation (>286 nm) of the deaerated benzene solution, the apparent rate constant for the main-chain scission of poly(1NMA-co-BMA) was larger by 1·4 times than that of poly(1NMA). Although the <math><mtext>M</mtext><msub><mi></mi><mn>w</mn></msub><mtext>M</mtext><msub><mi></mi><mn>n</mn></msub></math> ratio of the copolymer decreased monotonously to 2·0, that of the homopolymer increased initially and then decreased with photoirradiation time. The characteristic change in the intensity of excimer emission relative to monomer emission with photoirradiation time was also observed for the homopolymer system.</div>","PeriodicalId":101036,"journal":{"name":"Polymer Photochemistry","volume":"5 1","pages":"Pages 231-242"},"PeriodicalIF":0.0,"publicationDate":"1984-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0144-2880(84)90035-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81205679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Non-radiative excitation energy transfer from a statistic copolymer to acceptor in fluid solutions 流体溶液中从统计共聚物到受体的非辐射激发能转移

Polymer Photochemistry Pub Date : 1984-01-01 DOI: 10.1016/0144-2880(84)90054-X

K Sienicki, C Bojarski

引用次数: 2

Photochemistry in solid matrices: Laser flash photolysis of benzophenone in polymethyl-methacrylate and polystyrene matrices 固体基质中的光化学:二苯甲酮在聚甲基丙烯酸甲酯和聚苯乙烯基质中的激光闪光光解

Polymer Photochemistry Pub Date : 1984-01-01 DOI: 10.1016/0144-2880(84)90034-4

Ali Salmassi, Wolfram Schnabel

{"title":"Photochemistry in solid matrices: Laser flash photolysis of benzophenone in polymethyl-methacrylate and polystyrene matrices","authors":"Ali Salmassi, Wolfram Schnabel","doi":"10.1016/0144-2880(84)90034-4","DOIUrl":"10.1016/0144-2880(84)90034-4","url":null,"abstract":"<div>Benzophenone triplets were produced in matrices of polymethylmethacrylate (PMMA) and polystyrene (PSt) at concentrations up to ca. <math><mtext>6 × 10</mtext><msup><mi></mi><mn>−4</mn></msup><mtext>m</mtext></math> upon irradiation with single flashes of 347 nm light. With PMMA matrices a single triplet decay mode following first-order kinetics was observed at T ≤ 150 K and at T ≥ 410 K. Two distinct modes of triplet decay were observed in the temperature range in between: a fast first-order process, the lifetime (ca. 4 μs at 295 K) being independent of the initial triplet concentration [T]0, and a slow second-order process, the first half-life being proportional to [T]0−1. Similar results were obtained with PSt matrices. At temperatures between 180 and 350 K two modes of triplet decay were also observed, a fast first-order and a slow second-order process. From these results it is concluded that T-T annihilation is an important deactivation route between the glass temperature range and Tγ, where the rotation of α-methyl groups (PMMA) and of phenyl groups (PSt), respectively, commences. Above Tg, deactivation processes involving matrix molecules become dominant. Hydrogen abstraction, evidenced by the absorption spectrum of ketyl radicals, occurs to some extent here. Moreover energy transfer from vibronically excited triplet levels to chromophores of the matrix is feasible at elevated temperatures.On the basis that T-T annihilation is a diffusion-controlled process, the application of Smoluchowski's equation yields, for the temperature range between Tγ and Tg, diffusion constants much higher than expected. This indicates a strong reduction of the micro-viscosity of the matrix if benzophenone is admixed.</div>","PeriodicalId":101036,"journal":{"name":"Polymer Photochemistry","volume":"5 1","pages":"Pages 215-230"},"PeriodicalIF":0.0,"publicationDate":"1984-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0144-2880(84)90034-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90840149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 13

Effects of additives on photodegradation of polymers: Photosensitized crosslinking of poly(vinyl chloride) 添加剂对聚合物光降解的影响:聚氯乙烯光敏交联

Polymer Photochemistry Pub Date : 1984-01-01 DOI: 10.1016/0144-2880(84)90023-X

T.A. Skowronski, J.F. Rabek, B. Rånby

引用次数: 4

Excimer formation and energy transfer in vinyl(aromatic polymers) 乙烯基(芳香族)聚合物中的准分子形成和能量转移

Polymer Photochemistry Pub Date : 1984-01-01 DOI: 10.1016/0144-2880(84)90029-0

D. Phillips, G. Rumbles

引用次数: 12

Photolysis of poly(4,4-dimethyl-1-penten-3-one) 聚(4,4-二甲基-1-戊-3- 1)的光解反应

Polymer Photochemistry Pub Date : 1984-01-01 DOI: 10.1016/0144-2880(84)90071-X

Ikuo Naito, Kenji Imamura, Hisato Shintomi, Kazuyuki Okamura, Akihiro Kinoshita

引用次数: 2