热塑性淀粉/聚乙烯共混体系的研究进展

分析了近年来热塑性淀粉的研究现状,综述了热塑性淀粉(TPS)与聚乙烯(PE)共混体系的研究进展。归纳出淀粉含量、塑化剂、加工设备和方法以及PE和淀粉的种类等因素,特别是增容剂对共混体系微观形态、机械性能和降解性能的影响较大,并展望了TPS/PE共混体系今后的发展方向。     

单宁酸改性水性聚氨酯的制备及其性能

采用预聚体合成法,分别以二羟甲基丁酸(DMBA)、单宁酸(TA)为亲水扩链剂和内交联剂制备改性水性聚氨酯(WPU)乳液,利用FTIR,XRD,TG等分析方法对TA和WPU进行表征,考察了TA用量对WPU胶膜热稳定性、耐溶剂性、力学性能及WPU乳液粒径的影响。实验结果表明,TA已引入聚氨酯主链,TA改性后的WPU胶膜热稳定性增强;随TA用量的增加,WPU胶膜力学性能得到改善,当TA用量从0增加至0.90%(w)时,断裂伸长率从3 33.38%降至241.27%、拉伸强度从4.60 MPa增至8.58 MPa、吸水率从55.0%降至24.6%、乳液粒径从37.51 nm增加到42.18 nm。合成的WPU符合可持续高分子材料的要求,可用于环保材料中,对石油资源造成的能源危机有所缓解。     

单宁酸改性水性聚氨酯的制备及其性能北大核心CSCD

采用预聚体合成法,分别以二羟甲基丁酸(DMBA)、单宁酸(TA)为亲水扩链剂和内交联剂制备改性水性聚氨酯(WPU)乳液,利用FTIR,XRD,TG等分析方法对TA和WPU进行表征,考察了TA用量对WPU胶膜热稳定性、耐溶剂性、力学性能及WPU乳液粒径的影响。实验结果表明,TA已引入聚氨酯主链,TA改性后的WPU胶膜热稳定性增强;随TA用量的增加,WPU胶膜力学性能得到改善,当TA用量从0增加至0.90%(w)时,断裂伸长率从3 33.38%降至241.27%、拉伸强度从4.60 MPa增至8.58 MPa、吸水率从55.0%降至24.6%、乳液粒径从37.51 nm增加到42.18 nm。合成的WPU符合可持续高分子材料的要求,可用于环保材料中,对石油资源造成的能源危机有所缓解。     

用于包装和耐用品的生物基树脂

先前宣布的用于包装和工程产品的三种来源于可再生原料的聚合物，目前可以从DuPont公司商业上获得。BiomaxTPS树脂和片材是一种来自澳大利亚Plantic技术公司的玉米淀粉基原材料。这种材料目前可以从DuPont包装及工业聚合物公司获得。含有85％到90％的可再生原料的Biomax TPS（热塑性塑料淀粉）树脂球粒以一种g—p注塑牌号和一种用于薄壁部件的高流动牌号出现。     

SBS／MMT复合改性沥青常规性能测试分析

利用苯乙烯-丁二烯-苯乙烯三嵌段共聚物（SBS）与蒙脱土（MMT）及其共混物分别对沥青进行了直接复合改性和共混物复合改性,测试了改性剂用量不同的SBS改性沥青、MMT改性沥青以及SBS与MMT质量比（m（SBS）／m（MMT））不同的共混物复合改性沥青的物理机械性能,同时还对不同m（SBS）／m（MMT）的SBS／MMT共混物复合改性沥青及SBS／MMT直接复合改性沥青的高温储存稳定性和相形态作了测试分析。结果表明,SBS／MMT共混物复合改性沥青的常规性能整体最优。     

聚丙烯/蒙脱土纳米复合树脂的结构、形态与性能

利用球形纳米蒙脱土(MMT)负载Ziegler-Natta催化剂制备了聚丙烯(PP)/MMT纳米复合树脂。复合树脂中的PP具有与普通PP相仿的等规度和熔点;可通过改变聚合条件调节复合树脂中PP的相对分子质量和MMT含量。采用SEM,WAXRD,POM,DMA,TG等方法研究了复合树脂的形态结构、结晶形态、流变行为、动态力学行为、力学性能、阻隔性能和热稳定性。表征结果显示,复合树脂颗粒呈球形,流动性良好;MMT片层均匀分散于PP基体中,MMT片层与PP基体的相容性较差,在熔融加工过程中会发生部分聚集。当MMT含量约为1.1%(w)时,复合树脂中可形成MMT的逾渗网络。当MMT含量为1.29%(w)时,复合树脂的综合力学性能较好。少量MMT的存在可提高复合树脂的液体阻隔性能和热稳定性。     

新型聚烯烃-淀粉母料掺混物

用于薄膜和注塑的新型聚烯烃一淀粉母料掺混物以大大减少“炭足迹”胜过PE、PP、可生物降解聚酯或PLA而自豪。由设在加拿大蒙特利尔的Cerestech公司开发的、一种蒙特利尔Ecole Polytechnique公司的技术开发和许可的副产品，Cereloy热塑性塑料一淀粉（TPS）掺混物目前可从第一个Cerestech许可证持有者，     

高渗透率高选择性Silicalite-1沸石膜的合成与表征

利用重复水热合成法在α-Al2O3陶瓷管上合成Silicalite-1沸石膜,并对合成的沸石膜进行了X射线衍射(XRD)和扫描电镜(SEM)表征,通过单组分气体渗透对膜的渗透性能进行检测。通过测试发现,H2／N2在常温常压下的理想分离因素为4.00,略大于H2／N2的Knudsen扩散比值3.74,而H2／C3H8的理想分离因素为25.96,远大于其Knudsen扩散比值4.69,H2的渗透率为4.44×10-6mol／(m2·s·Pa)。     

大型中空容器级高密度聚乙烯树脂的合成与性能

采用单釜淤浆聚合工艺合成出大型中空容器用高密度聚乙烯(HDPE)专用树脂,并对聚合物的力学性能、结晶性能及相对分子质量分布进行了分析表征。结果表明,氢气分压由0.4 MPa增加到0.8 MPa时,HDPE的熔体流动速率由0.141 8 g/min升高至2.008 8 g/min;1-己烯质量分数由1%增加到3%时,HDPE的密度由951.8 kg/m3降至916.9 kg/m3,熔点由134.90℃降至133.54℃;使用催化剂J可制得重均相对分子质量与数均相对分子质量之比值较大(18.40～46.05)且呈单峰或双峰分布的HDPE。     

有机硅增韧改性双酚A型环氧树脂

采用侧环氧化硅油、端环氧基硅油及其预反应物对双酚A型环氰树脂(E-51树脂)进行改性。考察了侧环氧化硅油、端环氧基硅油及其预反应物的用量对固化产物的拉伸强度、断裂伸长率和冲击强度的影响。采用SEM对固化产物的拉伸断裂面形态进行了表征。实验结果表明,侧环氧化硅油、端环氧基硅油胺预反应物对E-51树脂的增韧效果最好。100.0份(质量份数)E-51树脂经10.0份侧环氧化硅油和5.0份端环氧基硅油胺预反应物改性后,拉伸强度达到75.09 MPa,断裂伸长率达到19.73%,冲击强度达到21.33kJ/m~2;比100.0份E-51树脂经10.0份侧环氧化硅油改性的E-51树脂的拉伸强度、断裂仲长率和冲击强度分别提高了1.66 MPa,2.41%,7.73kJ/m~2。     

Controlling the barrier properties of polymer composites containing montmorillonite

The barrier and sorption properties of films based on composites of gelatin and siloxane rubber SKTN-A with additives of montmorillonite (MMT) have been studied. The barrier properties of the films have been evaluated from their permeability to dibromomethane and water by vacuum pervaporation. Using the example of these heteropolar liquids, it has been shown that the permeability of the composites can be regulated by introducing up to 7 wt % MMT into the polymer matrix. The barrier characteristics of the gelatin-MMT composites with respect to dibromomethane have been improved by a factor of 3–4 compared with the original polymer. In the case of a hydrophobic polysiloxane matrix, the effect of organomodified MMT* on the barrier properties is less significant.     

纳米塑料复合啤酒瓶的初步研制

研究了聚对苯二甲酸乙二醇酯(PET)／蒙脱土(MMT)纳米复合材料的合成工艺,讨论了MMT对PET聚合工艺及切片的形变和相变温度以及气体阻隔性能的影响。结果表明:PET／MMT纳米复合材料的合成工艺与普通聚酯切片的合成工艺相近,含MMT 3.0％的纳米啤酒瓶可耐95℃高温,对O2、CO2气体的阻隔性比普通聚酯瓶提高2~3倍。     

拘束度耦合模型计算管道焊接残余应力

焊接残余应力是造成焊缝开裂失效的主要原因,因而精确描述应力对于管道安全输送极为重要,而外加拘束是影响焊接应力分布的众多因素之一。为此,应用ANSYS仿真软件,采用实体—壳单元耦合建模方法,建立了拘束度与焊接过程的温度场和应力场耦合仿真模型,研究了拘束对油气管道焊缝应力的影响。同时,还基于自建的1套自拘束焊接试验装置,实现了不同拘束状态下管道的焊接,并通过应变仪采集焊接过程中的应力应变数据,与模拟结果进行对比,进而证明了ANSYS 仿真耦合模型的有效性。结果表明：①对于两端约束的钢管焊接对接接头,随着管长增加,焊缝处的轴向应力减小,在距离焊缝230 mm处的轴向应力亦减小;②焊趾处的塑性应变亦减小,整体焊接结构的拘束度降低;③焊接的管道残余应力随着拘束度的上升而增大,拘束情况对焊接残余应力的影响明显;④拘束度最大的0.5 m×0.5 m管子,其焊接残余拉应力最大可达140 MPa,高残余拉应力会严重削弱管道的整体性能。进而提出建议：加强管道建设期间的焊接施工管理,避免产生管道焊接时的强拘束。     

改性条件对蒙脱土结构的影响

采用机械化学法对蒙脱土进行了有机改性,并对改性土进行了机械研磨,研究了钠化、有机改性剂用量以及机械研磨对蒙脱土结构的影响,对产物进行了XRD和TEM表征。结果表明,钠化改变了蒙脱土的层间力和有序排布,导致层间有物质填充和片层弯曲变形;增大有机插层改性剂用量,蒙脱土的各片层会不均匀扩展;机械研磨对原土和钠化土片层结构影响不大;蒙脱土有机插层改性后,短时间机械研磨有助于提高其片层结构的规整性,研磨时间过长会逐渐破坏片层排布,研磨180 min后片层部分剥离。     

The effects of sulfide stress cracking on the mechanical properties and intergranular cracking of P110 casing steel in sour environments

Variation and degradation of P-110 casing steel mechanical properties, due to sulfide stress cracking (SSC) in sour environments, was investigated using tensile and impact tests. These tests were carried out on specimens, which were pretreated under the following conditions for 168 hours temperature, 60 °C; pressure, 10 MPa; H2S partial pressure, 1 MPa and CO2 partial pressure, 1 MPa; preload stress, 80% of the yield strength (σs); medium, simulated formation water. The reduction in tensile and impact strengths for P-110 casing specimens in corrosive environments were 28% and 54%, respectively. The surface morphology analysis indicated that surface damage and uniform plastic deformation occurred as a result of strain aging. Impact toughness of the casing decreased significantly and intergranular cracking occurred when specimens were maintained at a high stress level of 85% σs .     

有机蒙脱土的制备及插层剂的选择

以蒙脱土为原料 ,用季铵盐、有机胺盐作为插层剂与蒙脱土层间的离子进行交换 ,并且利用不同的插层方法 ,在不同的介质中制备出一系列有机蒙脱土。经红外光谱和X射线衍射表明 ,有机插层剂已进入蒙脱土的层间 ,有机蒙脱土的层间距由 1.2nm增加到 1.4～ 2 .3nm。对有机蒙脱土在甲苯中的流变行为进行了研究 ,发现改性蒙脱土能在甲苯中膨润。研究表明 ,以十八烷基胺盐酸盐为插层剂 ,利用水作介质得到的有机蒙脱土综合效果最好。     

水性聚氨酯/硅烷蒙脱土纳米复合材料的制备与性能

用硅烷偶联剂修饰蒙脱土,制备了水性聚氨酯/硅烷蒙脱土纳米复合材料。傅里叶变换红外光谱、X射线衍射和透射电镜表征结果表明,硅烷偶联剂对蒙脱土的表面进行了有效的修饰,合成水性聚氨酯的各单体在蒙脱土层间聚合,使片层间距达到了5.19nm。热重分析和力学测试表明,水性聚氨酯/硅烷蒙脱土纳米复合材料比纯水性聚氨酯具有更优异的热性能,当硅烷蒙脱土的质量分数为2%时,拉伸强度和断裂伸长率分别提高了56.4%和40.0%。     

间歇法合成2,4-二叔丁基苯酚的反应工艺研究——苯酚与异丁烯的烷基化反应

以异丁烯为烷化剂 ,在间歇反应釜中研究了苯酚烷基化反应合成 2 ,4二叔丁基苯酚的反应工艺。结果表明 :在强酸性阳离子交换树脂的催化下 ,反应可以在较温和的条件下顺利进行。在温度 3 66K,压力 0 .0 84MPa(常压 ) ,催化剂 /苯酚 (质量比 ) =7.0 %∶ 1 ,以苯酚计的通烯速率为 0 .84 kg/ (kg· h) ,反应器高径比为2 .1∶ 1时 ,2 ,4二叔丁基苯酚的单程收率可达 70 % (以苯酚计 )。将烷基化产物分离后 ,利用副产物间的歧化反应可使主产物的总收率达到 95%     

The assembly of a composite based on nano-sheet graphene oxide and montmorillonite

Graphene oxide(GO)nano-sheets were synthesized using a modified Hummers’method from graphite powder.The Raman spectrum of GO displayed a D-band at 1359 cm~(-1)and a G-band at 1594 cm~(-1).The I_D/I_Gvalue of GO was calculated to be 0.97,suggesting the formation of new sp~2 clusters upon reduction.A method was designed to investigate the assembly of the GO/montmorillonite(MMT)composite.After the addition of GO,the typical peaks of montmorillonite in FT-IR spectra shifted,indicating the assembly between GO and MMT.The D-band and G-band reduced sharply in the GO/MMT composite.More importantly,the D-band(1344 cm~(-1))and G-band(1574 cm~(-1))shifted significantly and the I_D/I_Gvalue of the GO/MMT composite was calculated to be 1.13,showing a change in the GO structure.In the addition of0.04 wt%GO to MMT,the value of interlayer space(d)was up to 13.0 A?measured by XRD due to the insertion of GOinto MMT.The evident increases in contents of carbon atoms(26.59%)and nitrogen atoms(3.44%)indicate that GO was successfully combined with MMT.The nano-pores and clay sheets were not observed in the SEM image of GO/clay,but obvious wrinkles,while flexible sheets were observed in the typical scanning electron microscopy images of GO.This further proves that GO was combining with clay.The TEM image shows that the GO nano-sheets were tiled on the surface of MMT sheets.This observation suggests that a stable assembly structure was formed between GO sheets and MMTsheets.The change in particle size of MMT with the addition of GO shows that interaction occurred between GO sheets and MMT sheets,which was further confirmed by the results of zeta potential.Adsorption and insertion were the main mechanisms to assemble GO and MMT.     

Anti-microbial effectiveness of relative humidity-controlled carvacrol release from wheat gluten/montmorillonite coated papers

Wheat gluten coated papers containing carvacrol (15wt%) as anti-microbial agent and montmorillonite (0-7wt%) as filler were investigated as anti-microbial controlled delivery systems. The carvacrol losses were followed during the coating process and storage time at 30∞C under controlled RH from 40 to 100% RH. Increasing MMT content limited carvacrol losses during the coating process. A mathematical model based on Fick’s second law was used to determine the apparent diffusivities of carvacrol from experimental data of kinetic release at 30∞C and controlled RH. Diffusivity values varied from 0.143 × 10^?14 m²/s (0wt% MMT, 40% RH) to 6.010 × 10^?14 m²/s (5wt% MMT, 100%RH) depending on both MMT% and RH. The carvacrol diffusivities increased with increasing RH, and the presence of a high amount of MMT (≥5wt%) accentuated the RH-induced effect. Specific aggregated structure was evidenced by SEM and TEM in the presence of carvacrol and 5wt% MMT creating a preferential pathway for carvacrol diffusion. The anti-microbial efficiency of the MMT-WG-coated papers toward Escherichia Coli was assessed and showed that the anti-microbial effect was related to the carvacrol diffusivity. The diffusivity coefficients were utilized to optimize the packaging characteristics required to develop an efficient anti-microbial system and were finally validated against Botrytis cinerea.