PP熔融接枝改性研究进展

聚丙烯作为一种非极性聚合物,其亲水性、染色性、粘结性及与其它极性聚合物和无机填料的相容性都很差,这大大限制了它的应用。因此,往往采用官能化的方法赋予聚丙烯以极性、反应活性和功能性。通过熔融接枝的方法,在聚丙烯链段上接枝极性单体,可以显著提高聚丙烯的极性,改善表面亲水性及染色性等。本文简要介绍了聚丙烯熔融接枝改性及其影响因素,并按接枝单体分类,综述了熔融接枝聚丙烯的研究进展、性能与应用,展望了其发展趋势。     

聚丙烯熔融接枝马来酸酐反应机理的研究

改变聚丙烯（PP）熔融接枝马来酸酐（MAH）反应中的单体和引发剂的浓度以及添加适当助剂,考察了接枝产物的接枝率和恒定剪切应力（600kPa)及温度（210℃）下的剪切粘度,验证了作先前所提出的PP熔融接枝MAH的反应机理。即：在PP熔融接枝MAH的过程中,过氧化物自由基在熔融接枝过程中直接引发MAH单体及MAH单体在聚丙烯的大分子链段发生β断裂前直接被其引发而产生的接枝反应是影响产物的接枝率和分子量的关键。在不改变单体和引发剂浓度的情况下,降低过氧化物自由基在熔融接枝过程中直接引发MAH单体反应的程度而提高聚丙烯的大分子自由基直接引发MAH单体的反应趋势,是提高接枝产物接枝率和分子量的有效途径。     

多组分单体熔融接枝聚丙烯及其性能研究

利用单螺杆挤出机研究聚丙烯的多组分极性单体熔融接枝，从而改善和提高聚丙烯的极性。红外和熔体流动速率的结果表明，对于单组分接枝体系，在适当的反应条件下，甲基丙烯酸缩水甘油酯、甲基丙烯酸羟乙酯等极性单体均可以接枝在聚丙烯上，但同时也伴随着较严重的聚丙烯降解。而采用多组分单体接枝体系，通过加入甲基丙烯酸缩水甘油酯和苯乙烯单体，或甲基丙烯酸羟乙酯和苯乙烯单体，能够有效地控制聚丙烯的降解，大幅度提高接枝率，     

聚丙烯熔融接枝中共单体的作用机理

聚丙烯树脂是当今最具发展前途的热塑性高分子材料之一,在聚烯烃与工程塑料,如与聚酰胺或聚酯的共混合金中,聚丙烯接枝共聚物则广泛地被用为相容剂．此外,聚丙烯接枝共聚物还广泛应用于极性添加物等,用于改善制品的表面喷涂性能．聚丙烯接枝共聚物是通过自由基熔融接...     

溶液法马来酸酐接枝氯化聚丙烯的研究

采用溶液法用马来酸酐对氯化聚丙烯接枝改性。考察了反应温度、引发剂浓度、单体浓度、溶剂用量等因素对接枝率的影响，测定了反应前后氯含量的变化。采用FT-IR和DSC对产物进行了表征。     

聚丙烯熔融法接枝HEMA的研究

采用熔融接枝法制备了聚丙烯接枝甲基丙烯酸β－羟乙酯考察了反应温度，反应时间，甲基丙烯酸β－羟乙酯及过氧化二异丙苯浓度对甲基丙烯酸β－羟乙酯接枝率的影响，同时，用红外光谱对接枝物进行了定性表征，测定了接枝物的拉伸性能。     

聚丙烯多单体熔融接枝及其共混物研究

概括了聚丙烯多单体熔融接枝及其共混物的研究及发展状况,总结了现阶段对多单体熔融接枝机理的研究现状,并提出需要进一步解决的问题。     

多单体熔融接枝聚丙烯的微相分离结构

用熔融接枝方法制备了一系列不同接枝率的GMA(甲基丙烯酸缩水甘油酯)/St(苯乙烯)多单体接枝聚丙烯[PP-g-(GMA-co-St)],基体聚丙烯包括均聚聚丙烯和共聚聚丙烯(乙烯的摩尔分数分别是6.0%,12%,33%).接枝聚丙烯经过分离提纯后,用四氧化钌(RuO₄)进行染色,然后用透射电子显微镜(TEM)观察其微观形态.发现在接枝聚丙烯中形成了长程有序的、球状的微相分离结构,这种在分子量和分子结构都是多分散体系中形成的微相分离结构尚未见报道.同时,研究了基体聚丙烯中乙烯链段的含量以及接枝率对于接枝聚丙烯微观形态的影响.     

熔融法得到PP—g—HEMA性能的研究

由熔融法制得聚丙烯接枝甲基现人烯酸β－羟乙酯，用毛细管流变仪，示差扫描量热计、广角Ｘ－射线衍仪，结晶速率仪、偏光显微镜等对接枝物的流变性能和结果性能进行了定性，定量表征 ，比较了接枝前后聚合物结晶形态的变化。     

马来酸酐-苯乙烯熔融接枝聚丙烯的影响因素及其性能研究

用单螺杆挤出机制备了马来酸酐 (MAH) 苯乙烯 (St)对聚丙烯 (PP)的多组分单体自由基熔融接枝体系 .研究证实了当两种单体物质的量比约为 1∶1时 ,接枝物的接枝率最高 ,而熔体流动速率 (MFR)最大 .对反应体系影响因素的研究表明单体用量和引发剂用量对不同单体用量比的系列接枝物的接枝率会产生不同的影响 ;另外 ,单体用量增加 ,接枝物的MFR减小 ,过氧化二异丙苯 (DCP)用量增加 ,接枝物的MFR增加 .对多单体熔融接枝聚丙烯PP g (MAH co St)的力学性能研究发现 ,选用合适的单体用量比、单体用量和DCP用量时 ,所制备的接枝物可具有与纯PP相当或更佳的力学性能     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.