Poly(ethylene glycol-co-propylene glycol) as a Macromolecular Plasticizing Agent for Polylactide: Thermomechanical Properties and Aging

Finding a Suitable plasticizer for polylactide (PLA) is necessary to overcome its brittleness and enlarge its range of applications. In this study, commercial PLA was melt-blended with a new plasticizer, an ethylene glycol/propylene glycol random copolymer [poly(ethylene glycol-co-propylene glycol) (PEPG)] with a typical number-average molecular weight of 1.2 kDa and an ethylene glycol content of 78.7 mol %. The thermal properties, crystallization behavior, and mechanical properties of the quenched blends and the properties of the blends after storage for 2 months under the ambient conditions were investigated in detail. The advantage of using PEPG is that it does not crystallize at room temperature and has good compatibility with PLA. The quenched PLA/PEPG blends were homogeneous and amorphous systems. With an increase in the PEPG content (5-20%), the glass-transition temperature, tensile strength, and modulus of the blends decreased, whereas the elongation at break and crystallizability increased dramatically. The cold crystallization of PLA resulted in phase separation of the PLA/PEPG blends by annealing of the blends at the crystallization temperature.

Possibility of design of nanodevices by confined macromolecular self-assembly

Computer simulation has revealed that dual nanostructures for the development of nanodevices as nanowires, optical nanofibres and nanobatteries be obtained by the self-assembly of block copolymers confined geometry. The formation of individual nanostructures depends on the structures of block copolymers the confinement geometry and the interactions block copolymers and the boundary of the confinement geometry. In order to obtain individual nanostructures experimentally, attention needs to be paid to the manufacture of the confinement geometry and the design of the interactions between block copolymers and the boundary of the confinement geometry, The recently developed lithography technique should make experiments successful.

Studies on the nature of the macromolecular condensed state of "nascent" ultra high molar mass polyethylene

Ultra high molar mass polyethylene (UHPE) powder as polymerized in a slurry process has been studied, in its nascent state, after recrystallization on rapid cooling from the melt and after hot compression molding to a film, by DSC, effect of annealing the recrystallized specimen at 120 similar to 130 degreesC, morphology by polarizing optical microscopy and small angle X-ray scattering. Based on the experimental results obtained the macromolecular condensed state of the nascent UHPE powder is a rare case of a multi-chain condensed state of non-interpenetrating chains, involving interlaced extended chain crystalline layers and relaxed parallel chain amorphous layers. On melting, a nematic rubbery state of nanometer size domain resulted. The nematic-isotropic transition temperature was judged from literature data to be at least 220 degreesC, possibly higher than 300 degreesC, the exact temperature is however not sue because of chain degradation at such high temperatures. The recrystallization process from the melt is a crystallization from a nematic rubbery state. The drop of remelting peak temperature by 10 K of the specimen recrystallized from its melt as compared to the nascent state has its origin in the decrease both of the crystalline chain stem length and of the degree of crystallinity. The remelting peak temperature could be returned close to that of the nascent state by annealing at 120 similar to 130 degreesC.

Polyaniline doped with macromolecular acids

Polyaniline was doped with sulfonated PS, PPO and PEEK. The properties of doped polyaniline depended on the processing method and the structure of main chain backbone of the macromolecular acid.

MACROMOLECULAR COMPLEX OF POLYANILINE WITH SULFONATED POLYSTYRENE

The macromolecular complex of polyaniline(PAn) was prepared using sulfonated polystyrene(SPS) with sulfonation degree (SD) from 5 to 60mol% and characterized.

Influence Of Micro-Impurity On Protein Crystal Growth Studied By The Etch Figure Method

The investigation of the effect of micro impurity on crystal growth by optical microscopy has been validated. The results showed that the growth rate of a lysozyme crystal was affected even if the concentration of impurity of fluorescent-labeled lysozyme (abbreviation, F-lysozyme) was very small. Different concentrations of F-lysozyme had different effects on crystal growth rate. The growth rate decreased much more as F-lysozyme concentration increased. The density of incorporated F-lysozyme on different grown layers of a lysozyme crystal during crystal growth was obtained from the results of flat-bottomed etch pits density. (C) 2008 Elsevier B.V. All rights reserved.

二氧化碳共聚物链结构控制与性能研究

二氧化碳是主要的温室气体，同时也是一种廉价的、取之不尽用之不竭的碳氧资源。以二氧化碳为原料合成可生物降解的脂肪族聚碳酸酯是二氧化碳固定和利用领域的重要课题，其中最受关注的是由二氧化碳和环氧丙烷共聚合所制备的聚碳酸丙烯酯（PPC）。高分子量PPC可用于制备连续薄膜，这类薄膜除了保持可生物降解性能之外，还具有较好的透明性，而且其室温下对氧气的阻隔性能优良，在食品保鲜和药品包装等方面有很大的应用前景。但是， PPC在高温（40℃以上）强度迅速下降、低温（15℃以下）脆性加剧，为使PPC象普通塑料如聚乙烯那样实现大规模化应用，必须解决其高温增强和低温增韧的难题。 从高分子链结构来看，PPC的分子链主要由弱极性或非极性基团构成，且普通PPC的区域和立体规整性较低，导致PPC中分子链间作用力较弱，而且是无定型结构，降低了PPC耐温性能和机械力学性能。本博士论文的主要的思路就是通过调控PPC的链结构来提高其分子间作用力，从而改善PPC的耐温性能和力学性能。本论文围绕PPC的近程结构和远程结构控制，提出了改进PPC 链结构的五个方法，即提高PPC的分子量、制备交联型PPC、合成区域规整结构PPC、合成等规结构PPC、合成等规-无规立体嵌段PPC。通过研究链结构变化对PPC 热性能和机械性能的影响，证明通过共聚物链结构的设计和调控，可以大幅度增强PPC 的分子间作用力，拓展PPC 的使用温度范围。本文的主要内容包括： 1．通过在Y(Cl3COO)3-ZnEt2-glycerine三元催化体系或通过在环氧丙烷和二氧化碳聚合反应体系中引入少量双环氧单体如乙二醇二缩水甘油醚、丁二醇二缩水甘油醚或新戊二醇二缩水甘油醚，合成了数均分子量超过20万的PPC。与数均分子量为10万左右的PPC相比，分子量在20万左右的PPC的起始热分解温度增加了37℃，一定程度上改善了PPC的加工性能和使用性能。 2．将提高聚合物分子量改善其耐温和力学性能的思路进一步延伸，提出了分子量“无限大”的交联聚合物思路。通过在二氧化碳与环氧丙烷共聚反应中引入少量含有双键的环氧化合物(烯丙基缩水甘油醚)，可以在基本上不影响聚合反应收率的前提下，得到侧链带双键的可交联的PPC。通过侧链双键的自由基反应，获得交联的PPC，其耐热性能、力学性能与未交联的PPC相比均有显著提高，大幅度提高了共聚物的尺寸稳定性。在65℃下未交联PPC的永久形变为17.2%，根据PPC交联程度的不同，交联PPC的永久形变在0-15%间可控，而且交联后的PPC仍然具有很好的生物降解性能。 3．通过在稀土三元催化体系中加入适量的路易斯碱，既保持了稀土三元催化剂可以得到高分子量PPC的优点，另外路易斯碱与活性中心配位，可提高活性中心的亲核性和环氧丙烷开环选择性，得到高分子量规整区域结构的PPC。聚合物的头尾连接最高达84.6%，数均分子量为136kg/mol。XPS研究证实路易斯碱与中心锌金属发生配位，提高了金属碳酸酯的亲核性，进而提高了活性中心进攻环氧丙烷单体的选择性，从而改善了PPC区域规整性。进一步研究了非均相稀土三元催化剂中多质子化合物配体以及手性多质子化合物配体对PPC区域结构和头尾连接的影响，结果表明电子效应是影响PPC区域结构的主要因素，为以后催化剂的设计和制备提供了依据。与高头尾结构的低分子量PPC不同，高头尾结构的高分子量PPC性能有了很大的改善。当头尾连接结构含量从69.7%增加到83.2%时，PPC的玻璃化温度增加8℃，起始热分解温度提高45℃，表明提高PPC的区域规整性确实可以改善其耐温性能。 4．利用二氧化碳和环氧丙烷(PO)共聚时，单体PO的开环方式决定聚合产物立体结构的特点，在Y(Cl3COO)3-ZnEt2-glycerin/PHEN催化体系下，通过S-PO与 CO2的共聚，制得数均分子量为97kg/mol的等规结构PPC。13C-NMR谱图证实聚合物为等规结构。 5. 通过简单的顺序加料方式，在Y(Cl3COO)3-ZnEt2-glycerin/PHEN催化体系下，通过S-PO/CO2和rac-PO/CO2嵌段共聚，制得数均分子量为139kg/mol的等规-无规立体嵌段PPC。13C-NMR谱图及分子量的数据证实聚合物为等规-无规立体嵌段结构。

主链热致液晶高分子的高有序液晶性研究

主链热致液晶聚芳醚酮，同时引入含联苯介晶基元和含取代侧基的破坏结晶基元，具有丰富的液晶相结构，是目前发现的少数几种具有高有序液晶性的聚合物之一。本论文利用热分析（DSC）、红外光谱（FTIR）、广角X－射线衍射（WAXD）、偏光显微镜（PLM）、电子显微镜（TEM）、电子衍射（ED）和原子力显微镜（AFM）等实验手段对主链热致液晶聚芳醚酮进行了结构和形态表征，研究了高有序液晶性及其在相变中作用。这不但对全面了解和认识液晶高分子的复杂相变过程有重要理论意义，同时对改善这类材料的性能和拓宽其应用范围有重要的实际意义。首先确定了主链热致液晶聚芳醚酮的高有序液晶相。DSC结果指出该共聚物呈现两个热力学一级相转变，即结晶相向液晶相和液晶相向各向同性相的转变。WAXD结果表明，该共聚物在液晶相温区形成高有序近晶结晶相结构，即同时呈现高有序液晶相和结晶的衍射特征，由低角度衍射峰确定液晶相具有多个亚层结构，由高角度衍射峰确定结晶相为正交晶系。通过ED、WAXD方法，确定所得的高有序近晶结晶相为垂直的正交相SC_E相。TEM、PLM观察到的单矢畴结构和镶嵌织构等也证明了高有序液晶相的存在。高有序液晶相的形成和发展过程对其后降温过程中的结晶相变有重要影响。从各向同性溶体慢降温时(≤10 ℃/min)，在液晶温区生成了较完整的高有序液晶相，其后直接转化成稳定的晶型I结构；从各向同性溶体快降温时(≥20 /min)，在液晶温区生成不完整的小尺寸高有序液晶相并成为另一种亚稳晶相（晶型II）的成核剂，而晶型II的生长速率很快，最终导致大量亚稳晶型II的生成。亚稳晶型II在较高温度下热处理可转化为稳定的晶型I。对于常规聚芳醚酮，可通过拉伸诱导和溶剂诱导晶型II的产生，而本文为首次发现液晶聚芳醚酮可通过控制降温速率诱导晶型II的产生。研究了液晶聚芳醚酮的共聚组成和侧基的空间位阻效应对液晶性的影响。当聚合物中侧基摩尔分类小于30％和大于80％时，样品不具有液晶性。仅当共聚物的侧基摩尔分数在30％－80％时，样品呈现液晶性，熔融相转变温度随共聚组成不同基本保持不变，这种变化规律与常规聚芳醚酮无规共聚物的呈“V”字形变化有显著的不同。不同侧基共聚物的液晶稳定性从小到大的次序为氯侧基PAEK<甲氧基 PAEK<叔丁基 PAEK≤苯侧基 PAEK<三氟甲基苯PAEK，说明空间位阻效应比分子极性效应对液晶稳定性的影响大，其符合Flory-Onsager空间位阻效应是决定液晶稳定性因素的观点，而否定了Maier-Sauper分子极性效应是决定液晶稳定性因素的观点。液晶聚芳醚酮具有非常丰富的液晶相态结构，包括低有序液晶相特征的纹影织构、扇形织构、焦锥织构；高有序液晶相特征的镶嵌织构、近晶相球晶织构、单矢畴结构；剪切力场诱导的指纹织构；非剪切作用下结晶诱导的单晶状条带结构；以及薄膜样品从溶体冷却结晶得到的单晶体和从非晶态冷结晶得到的球晶。单矢畴结构是有单一分子取向的有序微区，它是液晶高分子存在高有序液晶相一个有力的证据。研究表明液晶聚芳醚酮的单矢畴结构是由初始的多天畴结构经热处理转化而成的，具有正交晶系和分子链垂取向的特征。指纹织构是在液晶相与各向同性相转变温区受到机械剪切作用时形成的且非连续地分散在镶嵌织构中。研究表明指纹织构为正交晶体结构，整个指纹织构区域的分子链均垂直于膜平面，晶体的a轴和b轴的取向也基本一致。在主链热致液晶高分子中这种剪切诱导的指纹织构还是首次发现并被报道。单晶状条带结构是液晶聚芳醚桐熔体膜在高有序液晶相转化温区等温处理生成的。TEM结果指出条带呈明暗相间的周期性排列，其宽度约20nm；ED结果指出条带区域具有正交晶系的单晶状取向结构；条带的延伸方向为晶体的b轴方向；AFM结果指出条带结构的薄膜表面是凸凹起伏的。通过电子衍射、明场、暗场和样品倾转技术证明，这种结晶诱导的单晶状条带结构的成因来自于分子链的取向不同。条带结构在AFM高度图中的凸起部分（TEM明场像的暗区）分子链垂直于膜平面，而凹下部分（TEM明场像的亮区）分子链向b轴倾斜，最大倾角±20°。需要指出的是文献报道的条带结构，无论是剪切的和非剪切（结晶诱导或固化诱导）的条带结构，其分子链均平行于膜平面，而我们得到的条带结构的分子取向与其有显著的不同。这种单晶状条带结构的生成，除湿度和时间等影响因素外，膜厚度是决定性因素，只有当膜厚略大于分子链长度时，方导致结晶诱导的单昌状条带结构的形成，过剩的自由体积能以这种起伏的条 结构的方式得以释放。该聚合物在生成单晶状条带结构的同时，还形成大量的均相附生结晶形态，绝大多数附生结晶接触面为(100)_Ⅰ/(210)_Ⅱ和(010)_Ⅰ/(210)_Ⅱ，分别对应结晶b轴的夹角为32°和122°。液晶聚芳醚酮薄膜样品，从熔体冷却结晶得到了单晶体，从非晶态冷结晶得到了球晶。平放（flat-on）的单晶有规则的外形，从[001]方向的电子衍射图，可确定单晶区域为正交晶系，分子链（c轴方向）垂直于膜平面。AFM观察指出，单晶体表面平整度达分子水平，并成功地获得了分子晶格分辨像，测得的晶胞参数（a和b）与电子衍射结果基本一致，分子链端位于晶体表面，这意味着该聚合物的分子量分布很均匀。该分子晶格分辨像被《Macromolecular Rapid Communications》选作封面。

厌氧好氧一体化生物反应器处理发酵废水的中试研究

一体化反应器由于投资少、占地小、管理运行方便等优点而备受青睐。但现有的一体化反应器大都适用于处理中低浓度废水，耐受负荷普遍偏低。本课题研制出新型高效的厌氧好氧一体化生物反应器，旨在通过反应器结构优化、高效微生物载体研制、配合高效微生物菌剂技术处理中高浓度有机废水，实现高效和低耗，降低设备造价，提高反应器运行稳定性。 首先开展了菌剂对废水的适配试验。采用15种不同的微生物菌剂，以葡萄糖配水、中药提取废水、啤酒废水、氨氮配水为基质，分别测定了微生物菌剂的耗氧速率和厌氧比产甲烷速率，以其为指标比较了各菌剂对废水的适配性。根据结果选择活性高的14＃、8＃、10＃菌剂，在试验室进行了菌剂对废水的连续处理试验，取得良好的处理效果，为菌剂在厌氧好氧一体化生物反应器的小试、中试中的应用奠定了基础。 经小试研究后，又对厌氧好氧一体化生物反应器进行了处理发酵废水的中试研究。试验结果表明，反应器启动快，系统有机负荷2.72 kgCODm-3d-1时整个反应器去除率保持在84.5％～93.19％，在30多天内一次启动成功。冲击负荷试验中，系统总有机负荷最高可达到8.88 kgCODm-3d-1，系统去除率稳定在88.10％～96.88%，说明反应器处理效率高，抗冲击能力强。稳定运行期间，COD去除率可达90％以上，各项指标都能达到国家排放标准。 此外，对反应器配套系统高效菌剂、高分子复合颗粒载体进行了研究。结果显示，菌剂与反应器适配良好，各功能区形成了丰富、高活性的微生物，厌氧区颗粒污泥TS高达83.9 gL-1，VS/TS为56.9％～57.4％，比产甲烷活性为280～350 mLCH4 gvss-1d-1；好氧区固定化微生物TS高达1.921 gL-1，VS/TS为94.02～94.30％。对载体性能的研究表明，此高分子复合颗粒载体密度适中，易于流化，不易流失；粗糙多空，易于挂膜；且无生物毒害作用，稳定安全，是一种优良的生物载体。反应器各功能区对废水的降解过程分析，说明了反应器、菌剂、载体适配良好，在其协同作用下，实现了污染物的高效降解。 The integrated reactors were popular because of their characteristics such as little investment, small occupation of land, convenient of manage and running etc. But the present integrated reactors were mostly applied for treating wastewater of low concentration, the load tolerance was generally on the low side. A new type integrated anaerobic-aerobic bio-reactor was developed, which was conducted to treating organic wastewater of middle or high concentration by optimization of reactor structure, development of efficient microbe carrier and adaptation of high active microbial blends, to achieve high efficiency and low consume, reduce equipment cost, enhance running stabilization of reactor. The adaptability test of microbial blends on different wastewater was carried on firstly. Oxygen consumption rate and anaerobic specific activity of methane producing of 15 different microbial blends were measured separately taking glucose artificial wastewater, Chinese herb extracting wastewater, brewery wastewater and ammonia nitrogen artificial wastewater as substrate, by which the adaptabilities of different microbial blends to wastewater were compared. According to the results high active microbial blends 14#, 8# and 10# were selected and used in the continuous treatment of wastewater in the laboratory and had obtained good effect, which had laid a foundation for application microbial blends to small scale test and pilot test of integrated anaerobic-aerobic bio-reactor. After the small scale test, the pilot test of the integrated anaerobic-aerobic bio-reactor treating fermentation wastewater was carried on. The test results showed fast initiation of the reactor. When system organic load reached 2.72 kgCODm-3d-1the COD removal rate of the reactor was stable between 84.5%～93.19% and it initiated successfully in more than 30 days at a time. In the load shock test the maximum organic load of system could reach to 8.88 kgCODm-3d-1 and the COD removal rate could be stable between 88.10%~96.88% which indicated that the reactor was efficient for treating wastewater and had strong resistance to shock load. At stable running period the COD removal rate of the reactor was over 90% and each index of wastewater could reach to the national discharge standards. In addition, the high active microbial blends and the macromolecule compound granule carrier, the matching system of the reactor was studied. It showed that the microbial blends adapted well to the reactor and abundant and high active microbes were formed in each functional field. The TS of granule sludge in anaerobic field was as high as 83.9 gL-1, the VS/TS was 56.9%~57.4%, the specific activity of methane producing was 280~350 mLCH4 gvss-1d-1. And the TS of immobilized biological granule was as high as 1.921 gL-1, the VS/TS was 94.02%~94.30%. Study on the carrier showed that the self-made macromolecular compound granule carrier was moderate of density, easy of fluidization, unease of running off, rough and porous, easy of films fixation, no bio-toxic, stable and safe, was a kind of superior carrier. Analysis of degradation process in each functional field confirmed the reactor, microbial blends and carriers were in good adaptation and wastewater was decontaminated by their cooperation.

functional monomers and polymers.CXXXVI.effect of metal ions on the interaction of synthetic nucleic acid analogs

The effect of metal ions on the conformation of thymine-containing poly-D-lysine was studied by CD spectra in aqueous solution. Of the metal ions studied,only copper(Ⅱ)ion affected the conformation of mucleic acid analogs .copper(Ⅱ)ion also affected the specifically interacting system made up of thymine-containing poly-D-lysine and polyadenylic acid.

A strategy for synthesis of ion-bonded supramolecular star polymers by reversible addition-fragmentation chain transfer (RAFT) polymerization

We have developed a novel strategy for the preparation of ion-bonded supramolecular star polymers by RAFT polymerization. An ion-bonded star supramolecule with six functional groups was prepared from a triphenylene derivative containing tertiary amino groups and trithiocarbonate carboxylic acid, and used as the RAFT agent in polymerizations of tert-butyl acrylate (tBA) and styrene (St). Molecular weights and structures of the polymers were characterized by H-1 NMR and GPC. The results show that the polymerization possesses the character of living free-radical polymerization and the ion-bonded supramolecular star polymers PSt, PtBA, and PSt-b-PtBA, with six well-defined arms, were successfully synthesized.

A strategy for synthesis of ion-bonded amphiphilic miktoarm star copolymers via supramolecular macro-RAFT agent

Amphiphilic supramolecular miktoarm star copolymers linked by ionic bonds with controlled molecular weight and low polydispersity have been successfully synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization using an ion-bonded macromolecular RAFT agent (macro-RAFT agent). Firstly, a new tetrafunctional initiator, dimethyl 4,6-bis(bromomethyl)-isophthalate, was synthesized and used as an initiator for atom transfer radical polymerization (ATRP) of styrene to form polystyrene (PSt) containing two ester groups at the middle of polymer chain. Then, the ester groups were converted into tertiary amino groups and the ion-bonded supramolecular macro-RAFT agent was obtained through the interaction between the tertiary amino group and 2-dodecylsulfanylthiocarbonylsulfanyl-2-methyl propionic acid (DMP). Finally, ion-bonded amphiphilic miktoarm star copolymer, (PSt)(2)-poly(N-isopropyl-acrylamide)(2), was prepared by RAFT polymerization of N-isopropylacrylamide (NIPAM) in the presence of the supramolecular macro-RAFT agent. The polymerization kinetics was investigated and the molecular weight and the architecture of the resulting star polymers were characterized by means of H-1-NMR, FTIR, and GPC techniques. (c) 2008 Wiley Periodicals, Inc.

Preparation and properties of polyether pentaerythritol mono-maleate grafted linear low density polyethylene by reactive extrusion

A reactive type nonionic surfactant, polyether pentaerythritol mono-maleate (PPMM) was synthesized in our laboratory. PPMM was adopted as functionalizing monomer and grafted onto linear low density polyethylene (LLDPE) with a melt reactive extrusion procedure. FT-IR was used to characterize the formation of grafting copolymer and evaluate their degree of grafting. The effects of monomer concentration, reaction temperature and screw run speed on the degree of grafting were studied systematically. Isothermal crystallization kinetics of LLDPE and LLDPE-g-PPMM samples was carried out using DSC.

Strengthening carbon deposition of polyolefin using combined catalyst as a general method for improving fire retardancy

Combination of Ni2O3 and solid acid with Bronsted acid sites and Lewis acid sites (such as HZSM-5 and H-beta) could dramatically improve fire retardancy of polyolefin, including polypropylene and linear low-density polyethylene. This is mainly attributed to the formation of a large amount of residual char from degradation products of polyolefin in the intermediate stage of combustion. Thus, the amount of flammable components diffusing into the flame zone was small.