SiO_2气凝胶核/聚苯乙烯壳复合阻燃保温板实验研究

实验过程采用热压浸渍加入发泡剂方法制备发泡型Si O2气凝胶核/聚苯乙烯壳复合珠粒,当加入14份发泡剂珠粒在90℃、压力0.9 MPa条件下反应9 h制备得到发泡剂含量为7%左右的可发性复合珠粒。同时对其发泡成型的原理、工艺流程、影响因素及参数控制等进行了研究,实验结果表明,在蒸汽压力为0.4 MPa的条件下经40 s制备得到发泡倍率为20左右、密度为0.025 g/cm3的预发复合珠粒,再经过模塑蒸汽发泡,蒸汽压力0.35 MPa、通气时间180 s,最终制备出保温性能优异(导热系数可达0.026 W/(m·K))、力学性能良好的Si O2气凝胶核/聚苯乙烯壳复合保温板。     

聚丙烯可发性珠粒的制备及其发泡性能研究

以多官能团丙烯酸酯类单体为辐照敏化剂,在氮气氛围中经60Co-γ射线辐照,制备了高熔体强度聚丙烯（HNSPP）并以此为原料,制备了聚丙烯可发性珠粒。通过扫描电镜观察了可发性珠粒的泡孔形态,探讨了发泡剂、成核剂对珠粒密度的影响,测试了可发性珠粒模塑成型后的力学性能。结果表明:体系发泡剂含量为6份,成核剂SiO2的含量为2份的时候,聚丙烯可发性珠粒的发泡效果最好,珠粒密度最小为0.09 g/cm3,且力学性能较之普通聚丙烯发泡珠粒所得的制品有了很大的提高。     

发泡剂存在下甲基丙烯酸甲酯悬浮聚合制备热膨胀微球

通过戊烷发泡剂存在下的甲基丙烯酸甲酯(MMA)悬浮聚合方法制备热膨胀聚甲基丙烯酸甲酯(PMMA)微球,利用在线激光粒度分析仪和光学显微镜观察聚合过程中PMMA微球粒径和形貌的变化,并对微球的热膨胀性能进行分析。结果表明,存在戊烷发泡剂时,聚合温度对微球粒径及形貌变化的影响显著,当聚合温度(70℃)远高于戊烷沸点时,微球粒径变化存在悬浮聚合成粒的典型特征阶段(转变、准稳态、增长和恒定阶段),但最终微粒形貌较差,核-壳结构不完善,导致微球热膨胀性能不佳。当聚合温度(50℃)接近戊烷沸点时,聚合过程微球粒径增长阶段不明显,粒子表面光滑且核-壳结构完善,微球的热膨胀性能良好,稳泡温程为60℃(起始发泡温度为95℃,收缩温度为155℃),体积膨胀率达56倍。     

聚丙烯发泡颗粒的制备

本文对可发性聚丙烯珠粒的制备进行了基础性研究,重点研究温度和压力对发泡效果的影响,并得到了聚丙烯颗粒发泡的最佳工艺-在110℃,11.8Mpa时.发泡颗粒的密度达到0.118g/cm3.     

甲基丙烯酸甲酯-苯乙烯悬浮聚合共聚物粒度的控制

以过氧化二苯甲酰为引发剂,以聚乙烯醇-羟基磷酸钙复合分散体系为分散剂,采用悬浮聚合法制备甲基丙烯酸甲酯-苯乙烯共聚物珠粒.研究了单体配比、引发剂用量、分散剂用量、反应温度、搅拌速度对聚合物珠粒的影响;并用红外光谱对产物结构进行了表征.     

MG-MUF包覆阻燃EPS泡沫及力学性能研究

采用经Hummers法制成的改性石墨(MG)为阻燃成分,让其与经聚乙烯醇改性的脲醛树脂(MUF)进行原位插层聚合,得到的MG-MUF作为可发性聚苯乙烯(EPS)的包覆阻燃剂。选用最佳预发泡工艺处理的EPS珠粒为芯材,包覆剂在一定含量的复合型固化剂作用下与EPS珠粒共混,经热蒸汽膨胀模压成型。对包覆样板进行阻燃性能、保温性能和力学性能测试。结果表明,阻燃剂MG含量为20 %、包覆比为3：1的样板的极限氧指数为30.5 %,而其水平燃烧等级达HF1级,综合性能较好。     

大粒径甲基丙烯酸丁酯悬浮聚合物的制备

以聚乙烯醇1788(PVA)为分散剂,十二烷基苯磺酸钠(SDBS)为辅助分散剂,偶氮二异丁腈(AIBN)为引发剂,采用悬浮聚合法制备了甲基丙烯酸丁酯(BMA)均聚物珠粒。研究了单体比例、引发剂浓度、分散剂浓度、反应温度、搅拌速度对聚合物珠粒性能的影响;用傅里叶变换红外光谱(FI-IR)对聚合物珠状结构进行了表征、用热分析仪考查了聚合物的热性能。结果表明,通过悬浮聚合制得的均聚物珠粒粒径分布均匀,具有较好的热稳定性。     

环保型酚醛泡沫的制备

通过介绍以碳酸钠为催化剂合成可发性酚醛树脂的酚醛泡沫的制备方法,体现制备酚醛泡沫的过程中可发性酚醛树脂和固化剂作用均匀释放出充当发泡剂的CO2,整个过程安全、环保。并且对酚醛泡沫进行了性能测试。     

超临界二氧化碳/乙醇共发泡制备聚砜泡沫制品

以超临界二氧化碳(scCO_2)和乙醇为共发泡剂,通过釜压发泡的方法制备特种工程塑料聚砜(PSU)珠粒泡沫制品。研究了乙醇含量、发泡温度、饱和压力对PSU泡沫材料的泡孔结构和珠粒粘接的影响,阐明了共溶剂发泡与泡沫材料泡孔结构的关系。结果表明,乙醇的引入增加了scCO_2在PSU基体中的溶解度,降低了PSU的发泡温度(最低发泡温度为150℃),拓宽了PSU的发泡温度窗口,增大了泡孔尺寸和膨胀倍率。当乙醇含量为33. 9%,发泡温度为180℃,饱和压力为8 MPa时,PSU珠粒泡沫的平均孔径可达86. 0μm,膨胀倍率可达10. 9倍,泡孔密度为9. 4×10~5个/cm~3,其泡沫制品珠粒间粘接良好,力学性能优良,压缩强度可达7. 2 MPa。     

环保型酚醛泡沫的制备

通过介绍以碳酸钠为催化剂合成可发性酚醛树脂的酚醛泡沫的制备方法,体现制备酚醛泡沫的过程中可发性酚醛树脂和固化剂作用均匀释放出充当发泡剂的CO2,整个过程安全、环保。并且对酚醛泡沫进行了性能测试。     

Synthesis of copolymer beads with various phenolic derivatives attached via different linkages and their antioxidation activity

Macroporous copolymer beads with various phenolic derivatives introduced via three types of linkages—amide, methylene, and ether—were prepared from chloromethyl styrene/tetra(ethylene glycol) dimethacrylate copolymer beads. The antioxidation activity of these phenolic copolymer beads was investigated by the measurement of the inhibition activity against the hydroperoxidation of 1,4-dioxane. The phenolic copolymer beads with the dihydroxybenzene moiety exhibited the highest antioxidation activity, and the antioxidation activity of methylene- or ether-linked phenolic copolymer beads was higher than that of amide-linked copolymer beads. Thus, the antioxidation activity of the phenolic copolymer beads was affected by not only the kinds of phenolic moieties attached but also the type of linkage group. In addition, the swelling of the copolymer beads in an organic solvent was greatly affected by the linkage type of the phenolic copolymer beads. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis of macroreticular copolymer beads having various phenolic derivatives immobilized via different bond and their radical scavenging activity

The macroreticular copolymer beads (RCS‐4G) were prepared by suspension copolymerization of chloromethylstyrene (CS) and tetraethyleneglycol dimethacrylate (4G) in water, using cyclohexane as a diluent. Then, the copolymer beads carrying phenolic derivatives immobilized via amide, methylene, or ether bond were prepared by subsequent reactions of RCS‐4G with various phenolic derivatives. The radical scavenging activity against 2,2‐Diphenypicrylhydrazil (DPPH) of the copolymer beads carrying phenolic derivatives immobilized was investigated in toluene. It was found that the copolymer beads had high radical scavenging activity against DPPH. The order of the radical scavenging activity against DPPH of the copolymer beads carrying phenolic derivatives immobilized did not coincide with the order of inhibition activity against the generation of 1,4‐dioxane hydroperoxide. The radical scavenging activity against DPPH of the copolymer beads having phenolic derivatives immobilized via methylene bond or ether bond was higher than that of the copolymer beads having phenolic derivatives immobilized via amide bond. It was found that the radical scavenging activity of the copolymer beads having phenolic derivatives was affected by not only the kind of phenolic derivatives immobilized and bond groups through which phenolic compounds were immobilized, but also the swelling ratio of the copolymer beads in toluene. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4791–4800, 2006     

球形木质素珠体接枝丙烯腈的影响因素研究

利用反相悬浮聚合技术制备球形木质素珠体,再以Fe2＋/H202为引发体系,采用正交实验综合研究了球形木质素珠体与丙烯腈的接枝共聚反应的各种影响因素对珠体的接枝率和接枝效率的影响。结果表明：当m（单体）／m（基体）=10：1,反应时间为90min,反应温度55℃,Fe2＋浓度为0．03mmol／L,H202浓度为2．97mmol／L时,可以得到最佳的接枝率和较高的接枝效率,木质素一丙烯腈接枝共聚物的接枝率为780％,接枝效率可达76．0％。     

一种新型球形纤维素吸附剂的制备Ⅱ.纤维素/AMPS接枝共聚物的合成

以交联球形纤维素珠体为骨架,以2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为单体,通过接枝共聚的方法赋予球形纤维素吸附剂强酸型基团——磺酸基,因此首先合成出纤维素/AMPS共聚物,并进行制备条件的优选实验,得出最佳的制备工艺条件为:以Na2SO3/K2S2O8作为引发体系,引发剂的用量为2.5%,单体与纤维素的最佳比值为1.5∶1(W/W),反应温度40℃,反应时间4.0h。在上述工艺条件下,所制备出的纤维素/AMPS接枝共聚物的接枝率为46.9%,而AMPS的均聚物含量仅为5.4%。     

Synthesis and heavy metal ion adsorptivity of macroreticular chelating resins containing phosphono and carboxylic acid groups

Macroreticular copolymer beads were prepared by suspension polymerization of 4-vinylbenzyl chloride (VBC), divinylbenzene (DVB) and monomers with carboxylic ester groups like dibutyl maleate (DBM), dibutyl fumarate (DBF) and dibutyl itaconate (DBI) in the presence of toluene as diluent. The copolymer beads were phosphorylated at the chloromethylated phenyl rings with triethyl phosphite and hydrolyzed by an aqueous sodium hydroxide solution; the hydrolysis on the bead surface converted carboxylic ester/phosphonate groups into carboxylic acid/phosphono groups, respectively. The investigations on the metal ion chelation characteristics of the H-form copolymer beads revealed that they have good adsorptivity toward heavy metal ions like Pb²⁺, Cd²⁺ and Cu²⁺, and poor adsorptivity toward ions like Hg²⁺ and UO₂²⁺. The adsorptivity caused by the three carboxylic ester monomer derivatives was in the order DBM > DBI > DBF. Especially, the Na-form copolymer beads neutralized by alkali treatment were very available for the adsorption of all the metal ions under investigation.     

Expandable styrene/methyl methacrylate copolymer: Synthesis and determination of VOCs by combined thermogravimetry/differential thermal analysis‐gas chromatography/mass spectrometry

Parts cast of metals using expandable polystyrene foams may have an unacceptable amount of surface defects, such as lustrous carbon. The use of foams made of styrenic/acrylic copolymers can improve the quality of foam molds and metal parts made using such molds. Lost foam copolymer was synthesized by suspension copolymerization of styrene and methyl methacrylate. The polymerization was carried out in the presence of blowing agents. The decomposition products of lost foam beads were studied by a method composed of the thermogravimetry/differential thermal analysis (TG/DTA) and gas chromatography/mass spectrometry (GC/MS). With these systems, the TG/DTA data can be combined with a GC separation and MS identification methods. This combined method improves the analysis of the decomposition products of lost foam beads and enables the precise identification of the amount and the nature of volatile organic compounds (VOCs) trapped during suspension polymerization. The results obtained from the combined method were verified for the nature and amount of VOCs with the results of time‐conversion studies for copolymerization of monomers in the presence of different concentrations of blowing agent. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and adsorption aspect of crosslinked PVA-based blood compatible adsorbents for LDL apheresis

Macroporous poly(vinyl acetate-co-triallyl isocyanurate) beads were prepared with suspension polymerization method. The copolymer beads were transformed into poly(vinyl alcohol-co-triallyl isocyanurate) by ester exchange reaction. Epoxy group was than connected to the surface of poly (vinyl alcohol-co-triallyl isocyanurate) by the reaction of epichlorohydrin with the hydroxyl group of the copolymer. And carboxyl groups were immobilized through 1,6-hexanediamine or triethylenetetramine space arm or directly connected to the hydroxyl group on the copolymer beads. The blood compatibility and adsorption properties for low density lipoprotein (LDL) in human plasma of the resultant macroporous crosslinked PVA-based adsorbents were investigated.     

Synthesis of thermosensitive copolymer beads containing pyridinium groups and their antibacterial activity

Thermosensitive 4VP‐NIPAAm‐4G copolymer beads containing pyridyl groups were first prepared by suspension copolymerization of 4‐vinylpyridine (4VP), N‐isopropylacrylamide(NIPAAm), and tetraethylene glycol dimethacrylate (4G; crosslinking reagent) in a saturated Na₂SO₄ aqueous solution in the presence of surfactant and MgCO₃ as dispersants. Then the copolymer beads containing pyridinium groups were obtained by the quaternization of the copolymer beads with various alkyl iodides (CH₃I, C₄H₉I, C₈H₁₇I) in N,N‐dimethylformamide. The 4VP‐NIPAAm‐4G (15 : 97 : 3) copolymer bead and the 4VP‐NIPAAm‐4G copolymer beads quaternized with butyl iodide exhibited high thermosensitivity in water, although the 4VP‐NIPAAm‐4G copolymer beads quaternized with methyl iodide or octyl iodide hardly exhibited thermosensitivity. All the quaternized copolymer beads exhibited antibacterial activity against Escherichia coli (E. coli), although the 4VP‐NIPAAm‐4G copolymer bead did not. In particular, the copolymer bead quaternized with butyl iodide exhibited the highest antibacterial activity against E. coli at 30°C. It was also found that the antibacterial activity of the quaternized 4VP‐NIPAAm‐4G copolymer beads was greatly affected by not only chain length of alkyl groups in alkyl iodides, with which the 4VP‐NIPAAm‐4G copolymer beads were quaternized, but also by temperature of the solutions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Amidoxime copolymer beads containing Cu/Cu2O microparticles as a biocidal material for water disinfection

Macroporous crosslinked acrylonitrile‐divinylbenzene copolymer beads were synthesized by suspension polymerization technique. The beads were chemically modified to have amidoxime functional group, which was used as a solid support for anchoring copper microparticles. The copper ions loaded on the copolymer beads were reduced using strong reducing agent to have copper microparticles on the amidoxime copolymer beads. The size of copper particles formed depends upon the amount of copper ions loaded on the beads. The formation of copper microparticles on the copolymer was confirmed by instrumental analysis. The copper containing amidoxime copolymer beads were investigated for the biocidal activity. The size and the distribution of copper particles on the amidoxime copolymer beads influenced their biocidal activity. The biocidal activity was tested against two Gram‐positive bacteria, Bacillus subtilis and Staphylococcus aureus, and against two Gram‐negative bacteria, Pseudomonas aeruginosa and Escherichia coli. The beads containing copper particles showed better biocidal activity against the Gram‐negative bacteria when compared with the Gram‐positive organisms. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Poly(allyl glycidyl ether-co-ethylene glycol dimethacrylate) copolymer beads as support for covalent immobilization of l-aminoacylase

Porous epoxy-activated copolymer beads were synthesized as support for the covalent immobilization of Aspergillus melleus l-aminoacylase. Here, a series of copolymer bead were synthesized using either glycidyl methacrylate (GMA) or allyl glycidyl ether (AGE) as monomer units and ethylene glycol dimethacrylate (EGDM) as cross-linking agent. The effect of monomer used and the effect of amount of cross-linking agent on covalent immobilization of aminoacylase were studied. Furthermore, the effect of porogen on immobilization of aminoacylase was also evaluated. AGE-co-EGDM copolymer beads gave higher binding of aminoacylase than GMA-co-EGDM copolymer beads. AGE-co-EGDM copolymer beads synthesized with lauryl alcohol as porogen and having 150% cross-linked density (i.e. AGE-(L)-150) gave maximum enzyme binding. Under optimum conditions, AGE-(L)-150 copolymer beads gave about 130 U/g of aminoacylase activity which corresponds to 72.24% of activity yield. Immobilized aminoacylase showed a broader pH, higher temperature and extended storage stability.