原子力显微镜在聚烯烃研究中的应用

聚烯烃材料因其卓越的性能和较低的价格广泛应用于工农业、医疗卫生、军事、日常生活等领域。为了拓展聚烯烃材料的应用范围,表面功能化聚烯烃、聚烯烃与其他材料的共混物以及聚烯烃/无机纳米复合材料等得到了发展,并成为该领域的研究热点。原子力显微镜(AFM)是利用一个极为尖锐的针尖与样品间的相互作用力进行材料表面的形貌、物理和化学信息探测的一种技术,它在上述聚烯烃研究中发挥着重要作用。表面粗糙度是聚烯烃材料表面功能化研究中的重要参数之一,AFM技术则能够给出准确的表面粗糙度信息。由于AFM技术能够直观地观察各组分的混合状态及相分离情况,因此AFM技术成为聚烯烃与其他材料共混研究的重要手段之一。此外,AFM是一种非常有效的微纳米结构形貌的表征方法,在聚烯烃的结晶研究方面也得到了应用。本文简单介绍了AFM表面形貌观测的工作原理和工作模式,主要阐述AFM在聚烯烃材料研究中的三个主要应用:材料表面粗糙度、共混相分离以及结晶研究。     

反应性聚烯烃的分子设计、催化聚合及应用

通用高分子材料高性能化研究的一个主要内容是聚烯烃(聚乙烯和聚丙烯)的高性能化和功能化.但是,由于聚烯烃大分子的化学惰性,其化学(分子)改性和物理(材料)改性都存在很大困难.近年来,烯烃聚合催化剂技术不断进步,烯烃聚合理论研究持续深入,从而为通过分子设计手段以可控方式在聚烯烃中引入化学活泼基团而制备结构明确和组成均匀的反应性聚烯烃奠定了基础.本文从反应性聚烯烃的分子设计、催化聚合以及其在聚烯烃高性能化研究中的应用等几个方面综述了近年来反应性聚烯烃领域的研究进展,并对此领域今后的研究发展方向提出了建议.     

生物医用功能高分子专辑 前言

正生物医用功能高分子材料广泛用于疾病诊断与治疗、组织器官再生和功能替代、生物体免疫调控、生物安全控制等方面。生物医用功能高分子材料隶属于医疗器械产业。国务院印发的《中国制造2025》明确指出,要大力发展生物医药及高性能医疗器械。随着大健康时代的来临,生物医用功能高分子及产品转化迎来了新的发展机遇,目前该领域的科技产出和人才培养正在逐步提升。基于面向国家发展大健康产业和转变经济发展方式对生物医用高分子材料的重大战略需求,为了展示我国生物医用功能高分子的最新进展,并对其发展前景和趋势进行预测,《功能高分子学报》组织出版了生物医用功能高分子专辑,邀请了国内专注于功能高分子相关生物或医学应用和产品转化的7个研究团队,撰写综述7篇,主要涉及生物医用功能高分子的制备、功能化和表征及其在抗凝血医疗器械、抗氧化体系、药物递送载体、医用膜材料、医用胶黏剂、组织再生支架等领域中的应用。     

•前言•生物医用高分子

“生物医用高分子”是生物材料的最重要组成部分, 是保障人类健康的必需品; 其应用不仅挽救了数以千万计人的生命, 提高了生命质量, 且对医疗技术和保健系统的革新、降低医疗费用也具有引导作用. 同时, 生物医用高分子又是高分子材料科学的重要分支, 是21世纪高分子材料科学, 特别是功能高分子或精细高分子领域内非常活跃而又重要的前沿发展方向. 作为一类生物材料, 在使用过程中必然与生理系统(血液、组织、细胞等)或其组成部分(蛋白、酶、DNA、多糖、无机盐和各类生物小分子)相接触, 因此其研究与发展与生命科学和医学也密切相关. 生物医用高分子的特征之一是生物功能性(biofunctionality), 即能够对生物体进行疾病诊断、组织替换或修复; 之二是生物相容性(biocompatibility), 即材料引起适当的机体反应的能力, 是区别于其他高技术材料的最重要的特征, 包括不引起生物体组织、血液等不良反应. 现代医学的进步与生物材料的发展密不可分, 如各种介入诊断和治疗导管、药物传递控释系统、创伤和烧伤敷料、血管内支架、人工关节与功能性假体等已得到广泛的应用. 但是, 生物医用高分子材料涉及化学、材料、生物、医学以及物理等诸多学科领域, 其使用又与生理系统相接触, 因此该材料的研究与开发具有相当的难度和挑战.     

可注射水凝胶的制备与应用

可注射水凝胶在再生医学和药物控释等方面有着广泛的用途,是近年来生物医用材料领域新的研究方向.本文综述了近年来人们在可注射水凝胶制备和应用方面的研究进展,最后展望了其发展前景.     

壳聚糖基生物医用材料及其应用研究进展

壳聚糖是一种极具发展潜力的天然生物材料,其在生物医学领域的研究和应用越来越受到重视。阐述了壳聚糖及其衍生物作为生物医用材料的特性,介绍了壳聚糖基生物医用材料的应用现状和发展趋势。     

层状组装：先进药物控释涂层材料的新选择*

先进的药物控释体系和医用植入体是生物医用材料研究的重要内容,将两者有机结合构成的结合装置为采用药物控释的手段有效解决医用植入体面临的挑战,提升医用植入体的功能提供了新的可能。基于静电交替组装的层层组装技术具有操作简单,涂层组成、厚度可控,适用组装分子和组装基材种类广泛,利于保持药物活性等一系列优点,已成为先进药物控释涂层材料的新选择。本文从层状组装多层膜构建原位药物控释涂层的方法研究,对药物释放的调控和功能药物涂层研究三个方面对这一技术在该领域的应用进行了简要介绍。系统总结了层状组装作为先进药物控释涂层材料的优势。并针对将药物控释与医用植入体有机结合的要求,对现有层状组装涂层方法的不足和今后发展的方向进行了论述。     

基于气息图案法有序多孔薄膜的制备改性及应用进展

有序多孔薄膜在过滤分离、催化、生物医学等领域有重要的应用前景。在众多制膜方法中,气息图案法以其简便易行、制膜效果好、环保等特点得到了广泛关注。科学家们一直致力于采用不同的材料和手段来进一步提高气息图案法多孔薄膜的性能。本文结合了最新的研究状况,探讨了基于气息图案法有序多孔薄膜的制备、改性及应用进展,并对未来的发展方向作...     

抗凝血性高分子材料研究的进展

近年来,由于“精细化学”和人工器官的迅速发展,高分子材料在生物医学领域中的应用越来越广泛,医用高分子作为一门新兴的材料科学,对发展医学、探索生命的起源方面起着十     

官能团化聚己内酯的制备及其生物应用

聚己内酯(PCL)是一种疏水的、半结晶的、可降解的脂肪族聚合物,其具有良好的生物相容性、药物透过性和机械性能,在药物缓释和组织工程领域得到了广泛的关注。由于其结晶性强,亲水性差,生物降解速度慢,限制了其在生物医用领域更广泛的应用。聚己内酯的官能团化可实现对聚酯材料亲疏水性、降解速率等物化性质的调节,同时,活性官能团的引入便于对PCL的进一步化学修饰,有利于拓宽聚己内酯类材料的生物医用领域。本文详细介绍在聚己内酯骨架引入侧基官能团的化学方法,并简要阐述了官能团化聚己内酯在生物医用材料领域的应用。     

The effect of PVC on thermal and catalytic degradation of polyethylene, polypropylene and polystyrene by a continuous flow reactor

A continuous flow reactor was operated at atmospheric pressure and feed rate of 0–1.5 kg h⁻¹ for degradation of PE, PP and PS in presence of 1–2 wt% PVC. The degradation temperatures were between 360 and 440 °C depending on the feeding material. The influence of PVC, temperature and silica-alumina catalysts on degradation behavior and on the properties of the products was studied and discussed. Different effects were observed for binary PE/PVC, PP/PVC, PS/PVC and complex PE/PP/PS/PVC mixtures due to specific interactions between PVC and each hydrocarbon polyolefin. Silica-alumina catalysts decreased the Cl concentration in oils but it seems to generate high amounts of Cl-containing organic compounds in gases.     

Poly(vinyl chloride) on the way from the 19th century to the 21st century

Despite all the technical and economic problems and the public discussions on the environmental dangers and hazards of chlorine chemistry, poly(vinyl chloride) (PVC) is the second most produced plastic (with a worldwide capacity of about 31 million tons), placing after polyolefins and before styrene polymers. Presently, PVC production worldwide is growing at a rate of more than 4% per year. The application of PVC was first described in a patent in 1913, but only after 1930 did a sustained interest in PVC arise in several industrial laboratories. The most remarkable milestones in PVC history and their importance to the development of macromolecular chemistry are briefly described, and some present PVC research and industrial applications, with respect to polymerization, stabilization, bulk property modification, and chemical and material recycling of PVC waste, are discussed. Some actual selected topics include the emulsion polymerization of vinyl chloride with polymeric surfactants and controlled free-radical polymerization with nitroxyls, whereas ionic and metal organic initiators have not found any technical applications. Chemical reactions offer many possibilities for the modification of PVC, but they have been not used on a technical scale yet. Much work has been done on stabilization with nontoxic or metal-free systems. The bulk properties of PVC can be influenced by impact modification through the addition of graft copolymers or by blending with other polymers. Also presented are some problems and recent developments in PVC recycling. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 578–586, 2004     

Comparative Studies on Hydrophilic and Hydrophobic Segments Grafted Poly(vinyl chloride)

Poly(vinyl chloride) (PVC) is one of the mostly produced plastics in the world and is widely used in single-use medical devices.However,the additives that are often necessary for PVC arouse concerns of its safety,thus quests the modifications of PVC itself.In this study,poly(ethylene glycol) (PEG) and polydimethylsiloxane (PDMS) segments were grafted onto PVC backbone in similar ways,and the chemical structures of the modified PVCs were characterized by Fourier transform infrared spectra,X-ray photoelectron spectra,thermogravimetric analysis and differential scanning calorimetry.Moreover,the water contact angle,protein adsorption,platelet adhesion,cell attachment and proliferation on different material surfaces were studied and compared.It was found that both PEG and PDMS grafting yielded improvement on biocompatibility compared with bare PVC,while hydrophobic PDMS grafted PVC showed more effective on cell attachment and proliferation than that of hydrophilic PEG grafted PVC.     

聚烯烃锂离子电池隔膜的研究进展

随着信息技术时代的发展,锂离子电池被广泛应用,电池隔膜作为锂离子电池的重要组成部分越发引起大家的重视。聚烯烃锂离子电池隔膜由于其优异的机械性能和化学稳定性,以及相对廉价的特点,在锂离子电池发展初期就被研发应用,已成为锂离子电池隔膜的主流。本文综述了聚烯烃锂离子电池隔膜的制备方法,主要介绍了干法和湿法,及相关的产品。重点阐述了聚烯烃锂离子电池隔膜的性能需求和改性方法,主要包括隔膜的孔隙率、隔膜对电解液的亲和性以及热稳定性等方面。     

主链链端功能化聚烯烃的设计、合成及其应用研究新进展

设计与合成主链链端功能化聚烯烃已成为目前聚烯烃功能化研究的热点之一。本文首先对聚烯烃功能化研究进行了简要介绍,然后重点评述了主链链端功能化聚烯烃的设计、合成及其应用研究的新进展,并对其前景进行了展望。     

聚磷酸酯医用材料

聚磷酸酯是一种生物相容性好、结构较易进行修饰和功能化的生物降解高分子，可以应用于药物缓释材料、组织工程材料、动物体内显影剂等医用领域。本文论述了近年来的聚磷酸酯医用材料的研究进展，尤其是作为药物缓释材料的合成与应用情况。随着合成研究的深入，聚磷酸酯在医用材料方面的应用将更加引人注目。     

Hyphenation of a thermobalance to soft single photon ionisation mass spectrometry for evolved gas analysis in thermogravimetry (TG-EGA)

The potential of hyphenating thermogravimetry (TG) and soft photo ionisation mass spectrometry (EBEL-SPI-MS) for fundamental and applied research and material analysis has been demonstrated by a newly developed TG-SPI quadrupole MS coupling (TG-SPI-QMS). Thermal decomposition of three common plastics, polyethylene (PE), polystyrene (PS) and polyvinylchloride (PVC) has been studied. While the decomposition of PE and PS in inert atmosphere takes place in a one step process (main mass loss at about 490 and 420 °C, respectively), PVC decomposes in a two step mechanism. The organic signature of the PE decomposition shows homologous series of alkenes and polyenes, while PS is forming mainly styrene mono- and oligomers. In the PVC decomposition, firstly hydrogen chloride (HCl) is eliminated in a hydro-dechlorination reaction (1st mass loss step: 285–305 °C), this is accompanied by the emission of the carbon skeletons of small aromatics (predominately benzene and naphthalene). In the second step (2nd mass loss step: 490–510 °C), the residual cross-linked polyolefin moieties decompose under release of heavily alkylated aromatics, including larger PAH. Chlorinated aromatics are formed only in trace levels.     

Sum frequency generation and coherent anti-Stokes Raman spectroscopic studies on plasma-treated plasticized polyvinyl chloride films

Polyvinyl chloride (PVC) is a widely used polymer to which various phthalates are extensively applied as plasticizers. PVC materials are often treated with plasma to vary the hydrophobicity or for cleaning purposes, but little is known of the nature of the surface molecular structures after treatment. This research characterizes molecular surface structures of PVC and bis-2-ethylhexyl phthalate (DEHP)-plasticized PVC films in air before annealing, after annealing, and after exposure to air-generated glow discharge plasma using sum frequency generation (SFG) vibrational spectroscopy. In addition, we compare the vibrational molecular signatures on the surfaces of PVC with DEHP (at a variety of percent loadings) to those of the bulk detected using coherent anti-Stokes Raman scattering (CARS). X-ray photoelectron spectroscopy (XPS) and contact angle measurements have been used to analyze PVC surfaces to supplement SFG data. Our results indicate that DEHP was found on the surfaces of PVC films even at low weight percentages (5 wt %) and that DEHP segregates on surfaces after annealing. The treatment of these films with glow discharge plasma resulted in surface-sensitive reactions involving the removal of chlorine atoms, the addition of oxygen atoms, and C-H bond rearrangement. CARS data demonstrate that the bulk of our films remained undisturbed during the plasma treatment. For the first time, we probed the molecular structure of the surface and the bulk of a PVC material using combined SFG and CARS studies on the same sample in exactly the same environment. In addition, the methodology used in this research can be applied to characterize various plasticizers in a wide variety of polymer systems to understand their surface and bulk structures before and after systematic applications of heat, plasma, or other treatments.     

国外聚烯烃树脂工艺进展及新产品开发

从生产技术和新品种开发方面介绍了国外烯烃树脂最新进展情况，指出茂金属催化剂技术，Ｃａｔａｌｌｏｙ技术，Ｓｐｈｅｒｉｌｅｎｅ技术是人们开发研究的重点，特别是茂金属催化剂技术能按照用户的要求“定制”不同结构的聚合物，茂金属催化剂技术为开发更多的高性能聚烯树脂提供了可能。     

Pandemic-Driven Development of a Medical-Grade,Economic and Decentralized Applicable Polyolefin Filament for Additive Fused Filament Fabrication

A polyolefin with certified biocompatibility according to USP class VI was used by our group as feedstock for filament-based 3D printing to meet the highest medical standards in order to print personal protective equipment for our university hospital during the ongoing pandemic. Besides the chemical resistance and durability, as well as the ability to withstand steam sterilization, this polypropylene (PP) copolymer is characterized by its high purity, as achieved by highly efficient and selective catalytic polymerization. As the PP copolymer is suited to be printed with all common printers in fused filament fabrication (FFF), it offers an eco-friendly cost–benefit ratio, even for large-scale production. In addition, a digital workflow was established focusing on common desktop FFF printers in the medical sector. It comprises the simulation-based optimization of personalized print objects, considering the inherent material properties such as warping tendency, through to validation of the process chain by 3D scanning, sterilization, and biocompatibility analysis of the printed part. This combination of digital data processing and 3D printing with a sustainable and medically certified material showed great promise in establishing decentralized additive manufacturing in everyday hospital life to meet peaks in demand, supply bottlenecks, and enhanced personalized patient treatment.