敏化的3,4-聚异戊二烯-2,6-双(4’-叠氮苄叉)环己酮体系的光交联反应研究

本文对二苯甲酮敏化前后3,4-聚异戊二烯-2,6-双(4′-叠氮苄叉)环己酮体系的光交联反应进行了研究。证明了该体系的光交联反应以双氮烯和被二苯甲酮活化的大分子的外双键加成为主。     

异戊二烯和四氟乙烯-丙烯共聚物的光化学接枝反应

在紫外光作用下,二苯甲酮、蒽醌和安息香能通过夺氢反应使异戊二烯在四氟乙烯-丙烯共聚物中接枝,接枝反应按三重态自由基引发机理进行,接枝率随光照时间的增长而增加,但不会超过40%。和异戊二烯的自由基聚合反应不一样,接枝物中聚异戊二烯接枝链的微结构以3,4-和1,2-聚合为主,而前者以1,4-聚合为主。Ce⁺⁴及Fe⁺²-H₂O₂等氧化还原体系对该接枝反应不产生作用.极性溶剂四氢呋喃的加入,对接枝链微结构的影响很小。     

3,4-聚异戊二烯的磺化反应及其离聚体的结构研究

本工作合成了磺化的3,4-聚异戊二烯及其离子聚合体,IR和NMR谱图证明对3,4-聚异戊二烯的磺化反应是成功的,并且磺酸基团主要与3,4-链节的侧基双键发生反应。WAXD对磺化3,4-聚异戊二烯及其离聚体的研究表明,磺化度的增加使离聚体的结晶能力降低,SAXS结果表明,在离子含量为3.29mol％的离聚体中,未观察到离子簇聚集,只观察到多重离子对的散射。     

磁场作用下异戊二烯在四氟乙烯-丙烯共聚物表面的光化学接枝反应

<正> 我们已经报道了异戊二烯在四氟乙烯-丙烯共聚物(四丙共聚物)的光化学接枝反应,并且证实了该反应是按三重态机理进行的。但是无论是用二苯甲酮、蒽醌还是安息香作为引发剂,异戊二烯的相对接枝率都相当低,一般不超过40％。当相同体系的反应在外磁场中进行时,我们发现了一些有趣的现象,第一,异戊二烯的接枝率提高得很快,第二,接枝链中3,4-聚合的产物大大增加。这样,通过异戊二烯在四丙共聚物表面的接枝,我     

聚-3,4异戊二烯的x-射线研究

对聚异戊二烯的研究一直很活跃。含3,4-链节70%左右的晶性聚3,4-异戊二烯(3,4-PⅠ),是适用于室温下较理想的吸振材料,其晶体结构尚未见报导。     

负型光刻胶302

为满足我国电子工业采用大规模集成电路的需要,我厂和清华大学以及有关单位密切协作,初步试制成负型光刻胶302。负型光刻胶302是橡胶型光致抗蚀剂的一种。主体是高聚物系,由国产聚异戊二烯橡胶环化而成,在双叠氮型光交联剂的存在下(并加少量增感剂二苯甲酮),以二甲苯为溶剂配制而成,是一种感光胶液。其感光交联过程为:     

二烯烃的定向聚合(續)

三、聚二烯的結构与性能 1,4-聚异戊二烯的结构与物理机械性貭已經熟知,顺-1,4-聚合物相当于天然橡胶,反-1,4-聚合物相当于古塔布胶(杜仲胶)。3,4-聚异戊二烯已经制出,性能研究未见发表。     

正离子聚合制备具有双峰分布丁基橡胶及其结构性能研究

通过活性负离子聚合法制备了具有不同微观结构的聚(苯乙烯-b-异戊二烯-b-苯乙烯)三嵌段共聚物(SIp S),并将其作为正离子聚合的大分子单体.采用2-氯-2,4,4-三甲基戊烷(TMPCl)/2,6-二叔丁基吡啶(Dt BP)/倍半乙基氯化铝(Al2Et3Cl3)的正离子聚合引发体系,引发异丁烯、异戊二烯以及SIp S结构中可反应的双键,合成了具有双峰分布的支化丁基橡胶.研究表明,SIp S中聚异戊二烯的3,4-结构有着更高的反应活性,更容易参与正离子聚合.随着SIp S中聚异戊二烯段含量的增加,支化丁基橡胶的产率增加,分子量也随之增加,聚合物溶液的特性黏数降低.通过体积排斥色谱(SEC)(多角激光光散射仪/示差监测器/在线黏度仪)及GPC-UV联用等仪器对支化丁基橡胶进行结构表征.证实了SIp S成功参与接枝反应,制备的丁基橡胶存在支化结构,而且产生的高分子区聚合物并不是由大分子单体物理混合所产生的.相较于线性丁基橡胶,支化丁基橡胶有着更快的应力松弛速率和更佳的物理机械性能.     

~(13)C核磁共振研究稀土催化剂聚合双烯的机理

用~(13)C-NMR 方法测定了稀土顺丁二烯和聚异戊二烯链端结构及序列结构,从链端结构推测的聚合活性链端结构与前文是一致的。在聚异戊二烯中存在着“头-头”和“尾-尾”结构,这种结构引起活性链端甲基位置的改变,从而解释了稀土异戊二烯中3,4-链节的形成。测定了不同聚合温度对聚合物中顺、反结构含量的影响,可用活性链端的 anti-syn异构化加以解释。     

烷基苯磺酸作用下环化聚异戊二烯-双叠氮型感光性高分子光交联产物的降解反应

<正> 环化聚异戊二烯-双叠氮型感光性高分子是一类应用广泛的负性光致抗蚀剂。关于它的光交联反应机理,许多人曾进行过研究,但是当这种具有三维网络结构的光交联聚合物完成其抗蚀使命后,怎样把它干净、彻底地从被涂表面去掉,是微细加工中急待解决的问题。常用的溶剂浸泡、高温加氧灼烧和等离子氧去胶法都存在着这样或那样的问题     

氢醌对3,4-聚异戊二烯-2,6-双(4′-叠氮苄叉)环己酮体系的光交联反应的影响

关于聚二烯烃-双叠氮型感光性高分子的光交联反应机理,目前有Hepher的自由基机理和的非自由基机理之争。为了对该体系的光交联反应有更加本质的了解,我们对含氢醌的该感光性高分子进行光照,在对反应产物的分析中发现有苯醌和2,6-双(4′-氨基苄叉)环己酮存在,证明氢醌对活性双氮烯有猝灭作用。     

Wavelength effect on the photoinduced reaction of polymethylmethacrylate

Polymethylmethacrylate (PMMA) containing benzophenone (BP) was photo-irradiated with monochromatic radiation of wavelength 260–360 nm using the Okazaki Large Spec-trograph (OLS). On irradiation of PMMA films containing BP in air, the sensitized main-chain scission and photocrosslinking of PMMA took place simultaneously. These reactions are dependent on irradiation wavelength. The threshold wavelength for both reactions is found to be ca. 380 nm. The number of main-chain scission and amount of gel increased with the increase of BP concentration in PMMA. Photosensitized main-chain scission favors the irradiation of radiation at ca. 280 nm and photocrosslinking takes place efficiently with the exposure of 340 nm radiation. A possible mechanism for photosensitized reaction is proposed. © 1995 John Wiley & Sons, Inc.     

~(13)C-NMR研究3,4-聚异戊二烯的序列分布

Fe(acac)_3-Phen-AlEt_3 催化体系可使异戊二烯聚合成以 3,4-链节为主具有一定结晶性能的聚异戊二烯。本文对该聚合物的~(13)C-NMR 谱进行了全分析,研究了序列分布、微观结构。结果表明不同方法求得的微观结构含量很好地一致,说明对~(13)C-NMR 谱峰归属的正确性。并指出顺-1,4/3,4-序列中存在着头-头,尾-尾的连接方式,3,4-嵌段链节不足够长及存在反节可能是结晶度不太高的主要原因。     

Photocrosslinking of a novel α,ω‐unsaturated copolyamide: mass spectrometric study on model compounds with benzophenone as photoinitiator

The aim of this work was to understand the reactions involved in the photocrosslinking processes of a α,ω‐unsaturated copolyamide foreseen as a new UV‐curable powder coating. The crosslinking reaction was photoinitiated with benzophenone. In this paper, the photochemical reaction between benzophenone and several model compounds was investigated. The model compounds contained functional groups which could be present in copolyamide. The products resulting from UV curing were identified using a combination of high‐resolution mass spectrometry and MSⁿ experiments. The characterization of the products allowed localization of the hydrogen abstraction by the type II photoinitiator during UV curing and, consequently, the determination of the reactive sites of the unsaturated polyamide chain which were involved in the photochemical reaction. Copyright © 2009 John Wiley & Sons, Ltd.     

晶性3，4－聚异戊二烯的结构研究

采用ＷＡＸＤ、ＳＡＸＳ和Ｘ－射线平板照相法研究了不同聚合条件和拉伸倍数下的晶性３，４－聚异戊二烯的结构．结果发现，降低催化体系反应速度有利于产物结晶；不同的含氮类给电子试剂对聚合物的结晶结构影响较大．取向样品随着拉伸倍数的增加结晶度和长周期增大，微晶尺寸变小．ＳＡＸＳ的散射强度计算表明，该聚合物属多分散非均一粒子体系，微孔半径在３．５－１６．４ｎｍ间．     

晶性3，4－聚异戊二烯的结构研究

采用ＷＡＸＤ、ＳＡＸＳ和Ｘ－射线平板照相法研究了不同聚合条件和拉伸倍数下的晶性３，４－聚异戊二烯的结构，结果发现，降低催化体系反应速度有利于产物结晶；不同的含氮类给电子试剂对聚合物的结是昌结构影响较大，取向样品随着拉伸倍数的增加结晶度和长周期增大，微晶尺寸变小，ＳＡＸＳ的散射哟度计算表明，该聚合物属多分散非均一粒子体系，微孔半径在３．５－１６．４ｎｍ间。     

Photocrosslinking of elastomer systems—III Ultraviolet light induced reactions in EPDM and EPR blended with or modified by grafting of derivatives of benzophenone

Photocrosslinking experiments were performed in elastomeric polymer films (EPR or EPDM) that either contained benzophenone or some of its derivatives, or had been previously modified (EPDM) by grafting of benzophenone. This latter modification was performed by a series of Friedel-Crafts reactions. The resulting materials were characterized by i.r. and u.v. spectroscopy in conjunction with physical property measurements. The results allowed relationships between the properties of the photosensitizers in their excited states and their efficiency in the crosslinking processes to be established. The results suggest that each coupled polymer-photoinitiator exhibits a particular behaviour. Thus it appeared that, in the presence of oxygen, the hexadiene branches of the terpolymer can undergo various types of reactions. Moreover, the grafting of the photosensitizer onto the elastomer backbone was shown to enhance considerably the crosslinking reaction. It is possible to conclude that oxygen plays a substantial role in the photocrosslinking. Indeed it always enhances crosslink formation. It can be assumed that the photooxidation of the polymer backbone yields alkoxy and hydroperoxy radicals which can act as crosslink sites.     

Photodegradation of O-methacryloyl ketone oxime-methyl mechacrylate copolymers in the solid phase

Several kinds of copolymers bearing O-acyloxyimino groups were prepared and their photodegradabilities were examined. Copolymers of O-methacryloyl ketone (acetophenone, benzophenone, or 2-acetonaphthone) oxime and methyl methacrylate (or styrene) were photodegradable even in the solid phase but in the case of copolymers of O-acryloyl acetophenone oxime and methyl methacrylate (or styrene) both photodegradation and photocrosslinking were observed. From these results it was found that the photodegradability of the copolymers was not dependent on the comonomer (methyl methacrylate or styrene) but dependent on the structure of the monomer bearing O-acyloxyimino groups. From detailed analysis of photodegradation of the copolymer of O-methacyloyl acetophenone oxime and methyl methacrylate in the presence of benzophenone it was found that the benzophenone worked not only as a sensitizer for the decomposition of O-acyloxyimino groups but also as a plasticizer to assist segment motions of polymer chains and the diffusion of oxygen in the film.