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衣文报导了用偶氮二异丁腈为引发剂,苯或甲苯为反应介质,β-氯乙基乙烯基醚与柠康酸酐共聚合反应的研究.红外光谱及核磁共振谱证明反应产物为共聚物,较详细地研究了反应条件对单体转化率、产物分子量及分子量分布的影响。 相似文献
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前言 甲基丙烯酸甲酯和丙烯酸丁酯的单体结构十分相似,用普通化学方法分析比较困难。A.Kotera等曾对甲基丙烯酸甲醇和丙烯酸甲酯的共聚物组成进行过红外光谱测定。但对于甲基丙烯酸甲酯-丙烯酸丁酯共聚物的组成,用红外光谱法进行定量测定未见文献报导。本文参考A.Kotera等提出的计算被测分子特征基团个数的方法,用于测定甲基丙烯酸甲酯-丙烯酸丁酯共聚物的组成得到了较好的结果。 相似文献
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本文报导了双酚A聚砜(B)与对苯二酚聚砜(H)两组份含量不同的嵌段共聚物的X射线衍射结果,B链的加入,使共聚物的结晶性能被破坏,B/H为0.48(摩尔比)时,所得共聚物已呈现出完全非晶相结构的特征.由IGC及DSC实验测定,表明这两种聚砜链是相容的. 相似文献
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大分子单体(macromer)共聚合为合成结构确定的接枝共聚物提供了新途径,但用络合催化剂进行共聚的例子很少。前文报导了末端为降冰片烯(NB)的聚苯乙烯大分子单体PS-NB的合成及表征;现报告其与乙烯的共聚,以制备主干为聚乙烯(PE)、支链为聚苯乙烯(PS)的接枝共聚物PE-g-PS的初步结果。 相似文献
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一、导言 1954年Natta用Al(C_2H_5)_3-TiCl_3催化剂制得了全同结晶的聚丙烯之后,就开始用Ziegler型催化剂研究乙烯-丙烯及乙烯同α-烯烃的共聚合。到1957首次取得实验室成果,并发表了用Al(C_6H_(13))_3-VOCl_3所制得的乙-丙共聚物及其鑑定方法。此后,Natta等又发表了一系列的论文,论述了合成乙-丙弹性体的各种催化系统、共聚反应动力学、共聚物的硫化和弹性性能、乙-丙硫化胶的物理机械性能等。最近又发表了乙烯-丙烯-二烯烃三组分共聚物的硫化方法和性能。1961 Bier在广阔的组成(单体)范围內研究乙-丙共聚合,获得了可以作为塑料、薄膜、弹性体和能够处理纸张的可溶性共聚物;报导了乙-丙嵌段共聚物的制备方法和性能。Lukach,Kelly等又发 相似文献
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本文研究了稀土丁二烯-异戊二烯无规共聚物的低温转变性能。实验证明,这类聚合物的玻璃化转变温度、结晶速率和最大主级结晶值都随共聚比的变化而变化,当丁/异戊重量组成比为84/16时,系不完全结晶橡胶。从丁二烯-异成戊二烯共聚物(不同共聚比)的最大结晶速率温度(Tcmax)用外推法可求得稀土顺丁橡胶的最大结晶速率温度为-72℃,这在文献上尚未见报导。稀土顺丁橡胶的玻璃化温度(Tg)为-113℃,其Tcmax(°K)/Tg(°K)=0.796,而天然橡胶的Tcmax(°K)/Tg(°K)=0.814,两者具有与0.80相近的值。 相似文献
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在碱性条件下由羟端基聚砜与双酚A环氧氯丙烷相互作用下制取了聚砜-聚羟基醚嵌段共聚物。溶解度试验、红外光谱、动态和静态力学试验等证明产物确是嵌段共聚物。 相似文献
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Synthesis and characterization of trans-1,4-butadiene/isoprene copolymers: Determination of sequence distribution and thermal properties 总被引:2,自引:0,他引:2
Two series of trans-1,4-poly(butadiene-co-isoprene) copolymers(TBIR) were prepared using the catalyst system Ti Cl4/Mg Cl2-Al(i-Bu)3 at different reaction temperatures. All dyad and triads sequence distributions, the number-average sequence length and the sequence concentration of the copolymers were calculated according to 13C-NMR spectra. The influences of temperature and initial molar ratio of butadiene to isoprene(Bd to Ip) on the distribution of the chain segments in the TBIR copolymers were discussed. The correlation of copolymer compositions and thermal properties were also evaluated, which facilitated the understanding of controlling the degree of crystallinity and the transition temperature by changing Bd content and temperature. 相似文献
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本文比较了各种氯代钒酸酯-三异丁基铝体系催化丁二烯、丙烯交替共聚的活性,得出氯代钒酸二新戊酯-三异丁基铝体系催化活性最高。能制得高分子量的交替共聚物。研究了该催化体系的特点和聚合规律及提高共聚物[η]的途径。在-76--45℃温度范围内可以制得正[η]为1.7-2.6dl/g的丁丙交替共聚物,单体转化率在80%以上。通过分析鉴定,证明产物交替度在95%左右,反式1,4丁二烯组分含量在95%以上。 相似文献
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Dr. Marvin Langlais Dr. Nicolas Baulu Dr. Séverin Dronet Dr. Charlotte Dire Dr. François Jean-Baptiste-dit-Dominique Dr. David Albertini Dr. Franck D'Agosto Dr. Damien Montarnal Dr. Christophe Boisson 《Angewandte Chemie (International ed. in English)》2023,62(41):e202310437
Block copolymers based on polyethylene (PE) and ethylene butadiene rubber (EBR) were obtained by successive controlled coordinative chain transfer polymerization (CCTP) of a mixture of ethylene and butadiene (80/20) and pure ethylene. EBR-b-PE diblock copolymers were synthesized using the {Me2Si(C13H8)2Nd(BH4)2Li(THF)}2 complex in combination with n-butyl,n-octyl magnesium (BOMAG) used as both the alkylating and chain transfer agent (CTA). Triblock and multiblock copolymers featuring highly semi-crystalline PE hard segments and soft EBR segments were further obtained by the development of a bimetallic CTA, the pentanediyl-1,5-di(magnesium bromide) (PDMB). These new block copolymers undergo crystallization-driven organization into lamellar structures and exhibit a variety of mechanical properties, including excellent extensibility and elastic recovery in the case of triblock and multiblock copolymers. 相似文献
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The decay of free radicals produced in polybutadiene, polystyrene, and block copolymers of butadiene and styrene by γ irradiation at 77 K has been studied at ?110°C in the case of polybutadiene and at ?95°C for the other samples. The free-radical decay rate is best interpreted in terms of an equation based on a second-order decay mechanism of a fraction of the free radicals decaying in the presence of other nondecaying free radicals. Hydrogen gas accelerates the free-radical decay. Increase of radiation dose increases the fraction of the radicals that decay, while increase of the fraction of styrene segments decreases the decaying fraction. In pure polybutadiene the higher the cis content, the greater fraction of decaying free radicals, but the second-order decay constant is less in the high-cis-content polybutadiene and is also less at the higher dose, probably owing to the hindrance of the radiation-produced crosslinks on the free-radical decay. The decrease of the second-order constant with increase of dose is also true for all the block copolymers studied. 相似文献
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以1,4-丁二醇为引发剂、辛酸亚锡为催化剂,通过L-丙交酯(LLA)、乙交酯(GA)、ε-己内酯(CL)的开环共聚,制得了低分子量的端羟基结晶性LLA/GA共聚物(PLLGA)和CL/GA共聚物(PCG),分别以FTIR1、H-NMR、GPC、DSC对其微结构和热转变温度进行了表征,重点考察了其热转变温度的组成、分子量依赖性.结果表明,利用辛酸亚锡/二元醇引发开环聚合,通过改变单体配比和单体/引发剂配比,可方便地调控共聚物的组成和分子量;通过改变共聚物的组成和分子量,可在较宽的范围内调节共聚物的热转变温度,并得到了玻璃化温度和熔点与组成、分子量之间定量的经验关系式. 相似文献