Zeolite catalysts have found extensive applications in the synthesis of various fine chemicals. However, the micropores of zeolites impose diffusion limitations on bulky molecules, greatly reducing the catalytic efficiency. Herein, we explore an economic and environmentally friendly method for synthesizing hierarchical NaX zeolite that exhibits improved catalytic performance in the Knoevenagel condensation reaction for producing the useful fine chemical 2-cyano-3-phenylacrylate. The synthesis was achieved via a low-temperature activation of kaolinite and subsequent in-situ transformation strategy without any template or seed. Systematic characterizations reveal that the synthesized NaX zeolite has both inter-crystalline and intra-crystalline mesopores, smaller crystal size, and larger external specific surface area compared to commercial NaX zeolite. Detailed mechanism investigations show that the inter-crystalline mesopores are generated by stacking smaller crystals formed from in-situ crystallization of the depolymerized kaolinite, and the intra-crystalline mesopores are inherited from the pores in the depolymerized kaolinite. This synthesis strategy provides an energy-saving and effective way to construct hierarchical zeolites, which may gain wide applications in fine chemical manufacturing.

Two kinds of residue feedstocks with different properties were hydrotreated over the same catalysts under the same reaction conditions, and the effect of the feedstock properties on the hydrogenation activity of the catalysts was investigated.The results showed that different feedstocks have high sulfur removal efficiency, while the nitrogen removal efficiency and carbon residue conversion efficiency are relatively low.The properties of residual oil from different sources vary greatly, and their hydrogenation reactivity is different.For the feedstocks with lower sulfur, higher nitrogen and higher Ni/V atomic ratio, the metal removal efficiency, nitrogen removal efficiency and carbon residue conversion are lower.

The Pt-Sn/Al2 O3 catalyst has been successfully commercialized for propane dehydrogenation, but it is still highly desirable to further improve its catalytic performance for maximizing the utilization efficiency of noble metal Pt. Herein, this work demonstrates that doping Nb and Ta into Pt-Sn/Al2 O3 has great impacts on its structure, and significantly improved catalytic performances are achieved in Pt-Sn-X/Al2 O3 (X=Nb and Ta). It is found that the incorporation of Nb and Ta into Pt-Sn/Al2 O3 can promote the dispersion of Pt-Sn particles, which results in Pt-Sn clusters being highly dispersed at the surface of Al2 O3 . Moreover, the presence of Nb and Ta makes the SnOx species less reducible, and thus the Pt-Sn particles become more stable at high temperature. Systematic exploration allows to obtain the optimized Pt-Sn-Nb5.0 /Al2 O3 and Pt-Sn-Ta1.0 /Al2 O3 , and these two catalysts exhibit high initial propane conversion (above 43.8 % and 50.4 %) with propylene selectivity of above 98 %. Most importantly, they show excellent regeneration in propane dehydrogenation, and their catalytic performance can be completely restored by a simple calcination.

Nitrogen-doped microporous carbon, which features a uniquely tunable porosity, exhibits promisingly high adsorption prospects in the greenhouse gas capture and water treatment. Herein, we propose a series of novel Ndoped microporous carbons (CMPAn-C1000), and precisely tune their porosities via a direct pyrolysis of rigid conjugated microporous poly(aniline)s (CMPAn, n = 1, 2, 3) with pore size difference in a molecular level, as achieved by simply tuning their linkers with varying sizes, planarity, and symmetry. The CMPA3-C1000, with a satisfactory amount of nitrogen heteroatoms, high SBET of similar to 800 m(2) g(-1), and large ultra-micropore volume of 0.25 cm(3) g(-1), has excellent CO2 capture ability (i.e., 5.1 mmol g(-1) at 273 K, 1 atm) and Hg(II) adsorption performance (i.e., Qe = 571 mg g(-1); k(2) = 0.0031 g mg(-1) min-1), respectively. CMPA3-C1000 might perform chemisorption towards Hg(II), according to calculations using density functional theory and experimental data; nitrogen atoms in porous carbon contributed to this excellent Hg(II) adsorption.

Beta分子筛作为一种重要的催化材料,被广泛应用于石油化工、煤化工及环境保护等领域,但其常规的水热合成过程存在成本高、单釜产率低和废水排放量大等问题.本研究提出了一条基于天然矿物介尺度结构解聚-重组装的无溶剂绿色合成Beta分子筛的新路线,采用该路线所合成的Beta分子筛(Beta-Anhyd)含有丰富的介孔和大孔结构,且具有较商业Beta分子筛(Beta-Ref)更高的比表面积和更低的酸量,以其为载体,通过脱Al补Sn制备的Sn-Beta催化剂(Beta-Anhyd-Deal)在丙烷脱氢反应中表现出较参比催化剂(Beta-Ref-Deal)更加优异的催化性能.

Biodegradable poly(butylene adipate-co-terephthalate) (PBAT) was branched by dicumyl peroxide. Comparing with the linear PBAT, the branched PBATs characterized significantly improved strain hardening ability leading to a higher tensile strength. Rheological results showed that the branched PBAT samples displayed high elastic modulus and complex viscosity. Differential scanning calorimetry analysis indicated the double effect of branched structure on the crystallization which can promote the nucleation and also hinder the chains diffusion, ultimately, resulting in reduction in △Hc. The higher crystallization temperature was obtained which was meaningful to enhance the melt strength during the cooling process. The Mo method successfully described the nonisothermal melt crystallization behavior of linear and branched PBATs. In general, the total crystallization rate was controlled by the crystal growth rate. The activation energy of the branched PBAT samples as calculated based on Friedman equation was universally larger than the one of linear PBAT.

Abstract The effect of Joncryl ADR®-4368 (abbreviated ADR) and dicumyl peroxide (DCP) on poly(butylene adipate-co-terephthalate) (PBAT)/poly(lactic acid) (PLA) blend was investigated. Two different blending procedures were adopted: (1) one-step blending of all components for 8 min; (2) premixing of PBAT and ADR (or DCP) for 4 min followed by addition of PLA blending for 4 min. ADR and DCP were effective compatibilizers for the PBAT/PLA blend by one-step blending which were confirmed by improving the phase interface between PBAT and PLA, decreasing the dispersed phase size, increasing the elasticity, viscosity and tensile strength. Moreover, the addition of ADR into PBAT/PLA blend by two-step blending was more efficient than the one-step blending based on refined morphology and further increased tensile properties. The two-step blending was beneficial to produce a larger amount of PBAT-graft-PLA (PBAT-g-PLA) copolymers at the phase interface. However, DCP was added to the PBAT/PLA blend by the two-step blending which showed lower properties than one-step blending. DCP triggered free branching reactions in a fast way. Based on the character of compatibilizers, choosing properly blending procedures can enlarge the tensile properties. These results would be interesting for industrial polymer materials, and may be importance to the wider practical application of PBAT/PLA blends.

以合成的"软段"吡啶胺基铪配合物和"硬段"水杨醛亚胺锆配合物,在二乙基锌链转移剂作用下制备了窄分子量分布的乙烯/1-辛烯嵌段烯烃共聚物.结果表明,链穿梭聚合的活性(以铪催化剂计)能够达到34.8×106 g/(mol·h),辛烯插入摩尔分数达到了23.5％,烯烃嵌段共聚物的重均分子量可达到225 kg/mol,分子量分布较窄(分子量分布指数2.0～2.3),嵌段共聚物熔点能够达到115℃以上.通过调节吡啶胺基铪催化剂与水杨醛亚胺锆催化剂的比例可以调控共聚物的嵌段长度及分子量.

烯烃多嵌段共聚物是一种新型的聚烯烃热塑性弹性体,主要通过催化乙烯和1-辛烯链穿梭聚合制备得到多嵌段含"软段"和"硬段"的聚合物,其独特结构和性能已经成为新材料的研究热点.本文概述了烯烃嵌段多共聚物的结构和制备合成,并指出了烯烃多嵌段共聚物性能和应用前景.

Since the discovery of Ziegler-Natta catalysts for olefin polymerization in the 1950s, the production of polyolefins with a variety of properties has continuously grown with rapid development of catalyst technology combined with polymerization process innovation. For propylene-based polyolefin, various polyolefins with distinctive characteristic of mechanical and optical properties were made with specific catalysts in commercial industries owned especially by those large worldwide companies. In this chapter, Ziegler-Natta catalysts, metallocene catalysts, and post-metallocene catalysts for PP polymerization are discussed in detail. Gas phase, bulk, slurry, and solution polymerization processes, such as Spheripol (Basell), Hypol (Mitsui Chemicals), Unipol (Dow Chemical), Innovene (INEOS), Novelen (BASF), Spherizone (Basell), and Borstar (Borealis), developed by the industrial tycoons were reviewed. The molecular architecture of the PP-based polyolefins could be tailored precisely using specific high-performance catalyst in an appropriate polymerization process, and different types of PPs, including homopolypropylene (HPP), random copolypropylene (RPP), impact PP, PP-based block copolymer, functionalized PP, etc., are produced. The relationship between molecular structure and performance of the PP-based polyolefins is also discussed thereof.

采用X射线衍射仪测定了丙烯聚合用球形氯化镁载体的物相,借助扫描电子显微镜观察了载体形貌,对载体粒径及粒径分布、孔结构、热重等进行了表征,并对载体负载得到的丙烯聚合用催化剂进行了评价.结果表明:中试载体为醇镁复合物,具有较好的球形形态,粒径分布较窄,为中孔孔隙结构且孔径分布均匀;载体的醇、镁摩尔比为2.8～3.0,负载后,催化丙烯聚合的活性较高,所制聚丙烯的细粉含量低;中试载体的综合性能与自制小试载体及对比载体的性能相当.

Polypropylene (PP) is one of the most widely used polymers. In this paper, three types of PPs including random PP, impact PP, and impact PP with high clarity, were prepared through a 75 kg/h pilot-scale Spheripol II process. The three produced PPs were produced by the selection or combination the two loops and gas phase reactor and controlling the comonomer and hydrogen concentrations. The three prepared PPs then were pelleted with the clarified nucleating agent NX 8000 and tested for mechanical, thermal, and optical properties. Their molecular structures and rubber phase size were also investigated by GPC, 13C NMR, temperature rising elution fractionation (TREF), XRD, SEM analysis, etc. The results showed that the random PP (PP-1) and the impact PP with high clarity (PP-3) obtained excellent optical transparency with a haze of 12.5% and 13.5% due to their small rubber phase size (roughly ≤ 100 nm), while the impact PP (PP-2) obtained bad transparency with a haze of 98.8% due to the large rubber phase size (about 1 μm) caused by the poor thermal compatibility with the PP matrix. The rubber phase content and ethylene/propylene sequence distributions of the three PPs varied much and resulted in different impact strengths and stiffness properties. PP-2 had a high impact strength of 14.5 kJ/m2 due to the rubber phase generated in the gas phase reactor. Except for the optical transparency, PP-3 gained stiffness and toughness, with 914 MPa of flexural modulus and 25.1 kJ/m2 of impact strength due to the unique molecular structure of its rubber phase.

以Joncryl ADR 4380为扩链剂,采用熔融共混法制备了聚乳酸(PLA)/聚对苯二甲酸 – 己二酸 – 丁二酯(PBAT)/硅灰石复合材料.通过傅立叶变换红外光谱(FTIR)表征了结构,采用场发射电子扫描显微镜(FESEM)、差示扫描量热(DSC)仪等研究复合材料的形貌特征及热性能.FTIR结果表明,硅灰石与PLA/PBAT共混物之间没有发生明显的化学键合,其在PLA/PBAT共混物中是一种物理分散.FESEM照片显示,硅灰石在PLA/PBAT/硅灰石复合材料中形成了取向排列,并且随着硅灰石含量的增加,硅灰石与PLA/PBAT相之间的界面粘附力减弱;DSC分析显示,硅灰石的加入促进了PLA的结晶,使得其熔融温度向高温方向移动.添加少量硅灰石可以提高复合材料的力学性能,当添加1份硅灰石时,复合材料的拉伸强度从41.08 MPa增至44.89 MPa,缺口冲击强度从67.89 kJ/m2增至70.32 kJ/m2.

As a particularly promising new class of catalysts, pyridylamido hafnium catalysts show outstanding polymerization performance and the bridgehead substituents are located at a strategic place to control the macromolecular architecture. However, modifications of the catalysts from the alkyl bridgehead substituents are relatively unexplored. In this paper, a C-1 -symmetric tert-butyl substituted pyridylamido hafnium catalyst was designed and synthesized for homo- and copolymerizations of ethylene, alpha-olefin, and styrene. tert-Butyl pyridylamido hafnium showed intriguing polymerization performance because the bulky tert-butyl substituent on bridgehead created the Thorpe-Ingold-like "buttressing effect". This catalyst afforded narrowly dispersed polymers for olefin homopolyrnerizations and showed high isoselectivity for alpha-olefin polymerizations ([mmmm] > 99%), but was inactive for styrene polymerization because of 2,1-insertion of styrene. Copolymerizations of ethylene and alpha-olefins produced bimodal-distribution copolymers, while copolymerizations of ethylene and styrene were realized to produce monomodal-distribution copolymers with ultrahigh molecular weight.

Polyolefin is the most widely used and versatile commodity polymer. In this work, three types of polyolefin-based elastomers (PBEs) were adopted to toughen a high-flow polypropylene to improve its overall performance. The chain microstructures of these PBEs, including ethylene/1-octene (E/O) random copolymer from Dow Chemical′s polyolefin elastomer (POE), olefin block copolymers (OBCs) of E/O from Dow, and ethylene/propylene random copolymer from ExxonMobil’s propylene-based elastomer, were elucidated by GPC, 13C NMR, TREF, and DSC techniques. The mechanical, thermal and optical properties, and morphology analysis of the PP/PBE blends were also studied to investigate the toughening mechanism of these PBEs. The results showed that all three types of PBEs can effectively improve the Izod impact strength of the PP/PBE blends by the addition of the rubber compositions, at the cost of the stiffness. PBE-1 and PBE-2 were found to have a great stiffness–toughness balance with about 1700 MPa of flexural modulus, about 110 °C of HDT and 3.6 kJ/m2 of impact strength on the prepared PP/PBE blends by forming separated rubber phase and refined spherulite crystals. As a result, the OBC with alternating hard and soft segments could achieve a similar toughening effect as the E/P random copolymer. Surprisingly, no obvious rubber phase separation was observed in the PP/PBE-4 blend, which might be due to the good compatibility of the E/P random chains with the isotactic PP; therefore, the PP/PBE blend obtains great toughness performance and optical transparency with the highest Izod impact strength of 4.2 kJ/m2 and excellent transparency.

综述了近年来聚乳酸(PLA)/聚己二酸对苯二甲酸丁二酯(PBAT)复合材料的研究进展.通过添加反应性增容剂、增塑剂和韧性高分子聚合物,提高PLA与PBAT的相容性,通过添加无机填料和天然高分子聚合物提高PLA/PBAT复合材料的力学性能,重点介绍了增容改性和增强改性PLA/PBAT复合材料的研究成果,最后对PLA/PBAT复合材料的未来发展方向进行了展望.

综述了透明聚丙烯(PP)的市场开发情况,重点介绍了几种国内外透明PP产品的牌号及其性能,分析了改性透明PP的增透机理,并对其改性方法进行了详细的概述.最后,针对现阶段国内外透明PP研究和开发过程中存在的问题提出意见和建议,并对透明PP的未来发展趋势做出展望.

An isotactic polypropylene (iPP-1) resin with low melting temperature (Tm) is synthesized by a metallocene catalyst and investigated for melt-spun fiber applications. The structure, thermal and mechanical properties, and feasibility of producing fibers of a commercial metallocene iPP (iPP-2) and a conventional Ziegler–Natta iPP (iPP-3) are carefully examined for comparison. Tm of iPP-1 is about 10 °C lower than the other two samples, which is well addressed both in the resin and the fiber products. Besides, the newly developed iPP-1 possesses higher isotacticity and crystallinity than the commercial ones, which assures the mechanical properties of the fiber products. Thanks to the addition of calcium stearate, its crystal grain size is smaller than those of the two other commercial iPPs. iPP-1 shows a similar rheological behavior as the commercial ones and good spinnability within a wide range of take-up speeds (1200–2750 m/min). The tensile property of fibers from iPP-1 is better than commercial ones, which can fulfill the application requirement. The formation of the mesomorphic phase in iPP-1 during melt spinning is confirmed by the orientation and crystallization investigation with wide angle X-ray diffraction (WAXD), which is responsible for its excellent processing capability and the mechanical properties of the resultant fibers. The work may provide not only a promising candidate for the high-performance PP fiber but also a deep understanding of the formation mechanism of the mesomorphic phase during fiber spinning.

The charge density of the central metal atoms and band gap of the compounds were investigated by the Dmol3 software package in Density functional theory (DFT). The band gap of the ( n BuCp)2ZrCl2 compound was the smallest among the listed metallocene compounds, however, its reactivity reached 11.88 kg (mol h)-1 × 104 at the time of slurry polymerization, which was the most active among the catalysts enumerated by the compounds and also verified the Frontier orbital theory. The polymerization of the ( n BuCp)2ZrCl2 compound with olefins proceeded according to the α-agostic mechanism of the ground state and the transition state. Hydrogen molecules were released during the transition state and led to ( n BuCp)2Zr(Cyclopropyl)+ as the final product. The authenticity of the presence of hydrogen in the olefin polymerization gas was confirmed. The aggregation of hydrogen led to a decrease in the activity of the metallocene catalyst, and that was why the energy barrier caused by the first polymerization was much lower than the second polymerization. The present work would provide valuable insight into the characteristics of metallocene catalysts with high activity and low hydrogen evolution.

The condensed structure,basic properties and thermodynamic properties of three cast films were investigated respectively,which include the pilot cast film (MPE-1),which was produced by self-made metallocene catalyst and used as target product,another pilot cast film (MPE-2) made by imported metallocene catalyst and imported cast film (MPE-3) which were used for contrast products.The results show that the melt flow rate,density and relative molecular mass distribution of these products are similar,while the clearly different comonomer distribution in MPE-2 has made MPE-2 shows better tensile and tear properties than MPE-1 and MPE-3,however,its impact resistance and haze are inferior to those of MPE-1 and MPE-3.