用废EPS制备低毒清香型胶粘剂

以橙皮为原料提取精油并对其作GC分析,以精油、乙酸乙酯及丙酮作混合溶剂,用废聚苯乙烯泡沫塑料(EPS)制备胶粘剂;对制备胶粘剂条件作了正交分析,比较了该胶与市售白乳胶的性能差异。结果表明,橙皮提取的精油中柠檬烯质量分数高达96%;V乙酸乙酯/V丙酮/V精油=5/2/3的混合溶剂,对废EPS的溶解力最强。制备胶粘剂最优条件为:乳化剂0.75g,MAA3.0g,酚醛树脂2.0g,BPO0.30g。制备的低毒清香型胶粘剂,剥离强度为0.35kN/m。     

废EPS改性制备清香型乳液胶粘剂及粘接应用研究

以MAA(甲基丙烯酸)和PVA(聚乙烯醇)为主要原料,以BPO(过氧化苯甲酰)为引发剂,以乙酸乙酯、丙酮和废弃橙皮精油作为废EPS(聚苯乙烯泡沫塑料)的混合溶剂,制备了清香型废EPS改性胶粘剂。研究结果表明:当混合溶剂中V(乙酸乙酯)∶V(废弃橙皮精油)∶V(丙酮)=5∶3∶2时,其对废EPS的溶解力(8.20 g/10 mL)最强;采用正交试验法优选出制备废EPS改性胶粘剂的最佳工艺条件为w(EPS中MAA)=8%、w(EPS中BPO)=3%、反应温度70℃和w(胶液中PVA)=10.0%,此时改性胶粘剂胶接实木单板的剪切强度可达到0.825 MPa,并且其对织物纤维、纸张等胶接性能良好。     

NMR relaxation reveals modifications in rubber phase dynamics during long-term degradation of high-impact polystyrene (HIPS)

The microstructure of rubber-modified polystyrene after thermal ageing at 90 °C and multiple extrusion was analyzed by time-domain nuclear magnetic resonance (TD-NMR) in a non-destructive manner. The transverse magnetization decay behaviour observed in TD-NMR was related to the total rubber fraction and its cross-linking density. The data reveal different mechanisms of long-term rubber degradation in high-impact polystyrene (HIPS) during thermo-oxidation and multiple processing: Multiple processing causes a slight increase in the cross-linking density of the rubber phase, without appreciably altering the total amount of rubber fraction. Thermo-oxidation is accompanied by a significant overall decrease of the rubber fraction, an increase of the cross-linking density, and a pronounced increase of the non-crosslinked fraction (chain ends and fragmented segments). The NMR results correlate well with spectroscopic observations and moderately with macroscopic mechanical properties.     

SiO2/CS-AM-DMC无机-有机絮凝剂固液分离油田废弃钻井液

废弃钻井液的固液分离是钻井行业中的重要过程.作者采用水溶液聚合法,以壳聚糖(CS)为基础、辅以甲基丙烯酰氧乙基三甲基氯化铵(DMC)、丙烯酰胺(AM)、纳米二氧化硅凝胶制备了SiO2/CS-AM-DMC无机-有机絮凝剂.其形貌与结构经SEM、FT-IR表征,粘均分子量用乌式粘度计测定.考察了制备过程中破胶剂的种类,反应...     

聚苯乙烯/多壁碳纳米管复合材料的阻燃性能

综述了近年来聚苯乙烯/多壁碳纳米管复合材料的阻燃研究进展,详细介绍了其热解性能（包括热解温度和玻璃化转变温度）以及燃烧性能（包括热释放速率、质量损失速率和成炭性）,并对相关机理进行了深入的探讨,分析了多壁碳纳米管含量、长径比、杂质及表面改性处理对相应复合材料的热稳定性及阻燃性能的影响。     

Solvothermal synthesis of organically modified α‐zirconium phosphate‐based polystyrene nanocomposites and thermal stability

Polystyrene/α‐zirconium phosphate (PS/OZrP) nanocomposites were prepared based on the organically modified α‐ZrP(OZrP) with hexadecyltrimethyl ammonium bromide (C16) by solvothermal technique and solution refluxing. The structure of the PS/OZrP composites was characterized by X‐ray diffraction and high‐resolution electronic microscopy. The thermal behaviors of the composites obtained were investigated by thermogravimetric analysis. The maximum decomposition temperatures (T_max) of PS/OZrP nanocomposites prepared by solvothermal method increased gradually from 431 to 458°C with the increase of the OZrP loading from 0 to 20 wt %, and the amounts of the charred residue at 600°C (char wt %) had a remarkable increase from 1.6 to 17.1 wt %, respectively. Moreover, the TG results of the nanocomposites prepared by solvothermal method have more obvious enhancement in the thermal stabilities and especially in the amount of charred residue at 600°C (char wt %), which has a double increase from 4.2 to 8.5 wt % at the content of 10 wt % OZrP than by solution refluxing. All results suggested that the solvothermal method is an effective way for the preparation of PS/OZrP nanocomposites with the intercalated nanostructure, which led to the obviously improved thermal stability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122:593–598, 2011     

Polymer electrolyte membrane with nanomatrix channel prepared by sulfonation of natural rubber grafted with polystyrene

High‐proton‐conductive polymer electrolyte with a nanomatrix channel was prepared by graft copolymerization of styrene onto deproteinized natural rubber followed by sulfonation with chlorosulfonic acid. First, natural rubber latex was purified with urea in the presence of surfactant to remove almost all proteins present in the rubber. Second, graft copolymerization of styrene onto deproteinized natural rubber was carried out with tert‐butyl hydroperoxide/tetraethylenepentamine as an initiator at 30°C in latex stage. The graft‐copolymerized natural rubber (DPNR‐graft‐PS) was sulfonated with chlorosulfonic acid in chloroform solution at an ambient temperature. The resulting sulfonated DPNR‐graft‐PS was characterized by FTIR spectroscopy, solid state ¹³C CP/MAS NMR spectroscopy, elemental analysis, and transmission electron microscopy. High proton conductivity of about 0.1 S/cm, less water uptake of 24 wt % and comparatively good stress at break of 9 MPa were accomplished at suitable contents of styrene units and sulfur, i.e., 32 wt % and 75 mol %, respectively. The high proton conductivity, excellent stability, and good mechanical properties were associated with not only the formation of the nanomatrix channel but also a specific concentration of sulfuric acid group. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Influence of small rubber particles on the environmental stress cracking of high impact polystyrene

This article exploits the influence of rubber particle size (RPS) and rubber crosslinking on environmental stress cracking resistance (ESCR) of high impact polystyrene (HIPS), with special interest on the influence of small rubber particles fraction. Three commercial HIPS of high ESCR were selected and four batches of HIPS were prepared in‐house, including samples based on high cis and very high viscosity polybutadiene (PB). Their morphologies were analyzed by low angle laser light scattering, optical microscopy, and transmission electron microscopy, and the samples were submitted to flexural ESCR tests with fatty agents. The ESCR to sunflower oil was found to increase with the reduction of the rubber particles fraction smaller than 1–2 micron. Results have also confirmed that an increase in RPS is the key parameter to promote ESCR, although there is limit for RPS to be effective on ESCR improvement. The reduction of small rubber particles fraction in HIPS was achieved by using a high cis PB, that promotes low grafting efficiency of polystyrene onto PB backbone because of the low content of 1,2 vinyl isomer. Besides the ESCR improvements, HIPS with high cis PB showed higher elastic modulus and impact resistance than HIPS containing medium cis PB, which is desired for thickness reduction in food packaging and refrigeration cabinets. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation of well‐defined block copolymer having one polystyrene segment and another poly(styrene‐alt‐maleic anhydride) segment with RAFT polymerization

Block copolymers, polystyrene‐b‐poly(styrene‐co‐maleic anhydride), have been prepared by reversible addition‐fragmentation chain transfer (RAFT) polymerization technique using three different approaches: 1‐phenylethyl phenyldithioacetate (PEPDTA) directly as RAFT agent, mediated polystyrene (PS) block as the macromolecular PS‐RAFT agent and mediated poly(styrene‐maleic anhydride) (SMA) block with alternating sequence as the macromolecular SMA‐RAFT agent. Copolymers synthesized in the one‐step method using PEPDTA as RAFT agent possess one PS block and one SMA block with gradient structure. When the macromolecular RAFT agents are employed, copolymers with one PS block and one alternating SMA block can be produced. However, block copolymers with narrow molecular weight distribution (MWD) can only be obtained using the PS‐RAFT agent. The MWD deviates considerably from the typical RAFT polymerization system when the SMA is used as the RAFT agent. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Selective oxidation of olefins and aromatic alcohols with tert‐butylhydroperoxide catalyzed by polymer‐anchored transition‐metal complexes

Three polymer‐anchored metal complexes (Co, Cu, and Pd) were synthesized and characterized. The catalytic performance of these complexes was tested for the oxidation of olefins and aromatic alcohols. These complexes showed excellent catalytic activity and high selectivity. These complexes selectively gave epoxides and aldehydes from olefins and alcohols, respectively. Individually, the effect of various solvents, oxidants, substrate oxidant molar ratios, temperatures, and catalyst amounts for the oxidation of cyclohexene and benzyl alcohol were studied. Under optimized reaction conditions, 96, 81, and 71% conversions of cyclohexene and 86, 79, and 73% conversions of benzyl alcohol were obtained with Co(II), Cu(II), and Pd(II) catalysts, respectively. The catalytic results reveal that these complexes could be recycled more than five times without much loss in activity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011