秸秆粉的改性及其表面极性对木塑复合材料界面的影响

通过接枝苯乙烯对秸秆粉表面进行改性,采用毛细管上升法测定了秸秆粉、改性秸秆粉的表面接触角,依据Washburn方程和Owens法,求解2种秸秆粉的表面自由能及其极性和非极性分量,并通过电子拉伸试验机、扫描电子显微镜研究了不同秸秆粉对木塑复合材料力学性能、微观形貌的影响。结果表明,改性秸秆粉的表面自由能为24.77 mN/m,体现分子色散力的非极性分量为19.79 mN/m;而秸秆粉的表面自由能为18.90 mN/m,其非极性分量为3.75 mN/m,说明接枝共聚可有效地改善秸秆粉的表面极性;与聚合物复合时,改性秸秆粉比秸秆粉具有更好的界面融合性,改性秸秆粉在基体中的分散性优于秸秆粉。     

无三苯CR/SBS/MMA/BA自交联鞋用胶粘剂的研制

采用复合引发剂 ,以N 羟甲基丙烯酰胺 (NAM )及丙烯酸 (AA)为功能单体 ,与CR、苯乙烯 丁二烯嵌段共聚物 (SBS)、甲基丙烯酸甲酯 (MMA)和丙烯酸丁酯 (BA)进行多元共混接枝共聚 ,再配以混合型增粘树脂 ,研制出不含苯、甲苯和二甲苯 (简称三苯 )自交联环保型鞋用胶粘剂。探讨了SBS用量、MMA/BA配比、功能单体NAM及AA用量对胶粘剂粘合性能的影响。结果表明 ,CR/SBS/MMA/BA/AA/NAM自交联型接枝胶粘剂对非极性鞋材的粘合性能明显优于CR/MMA/BA三元接枝胶和CR/SBS/MMA/BA四元接枝胶。     

淀粉接枝共聚物瓦楞纸表面施胶增强剂的制备及其应用

利用无皂乳液聚合技术通过阳离子淀粉和苯乙烯(St)、丙烯酸丁酯(BA)等乙烯基单体进行接枝共聚反应,制备了一种淀粉接枝聚合物乳液,并对其表面施胶性能进行了研究。结果表明:当m(淀粉接枝乳液)∶m(氧化淀粉)=3∶100、w(硫酸铝)=0.4%和施胶液pH=4时,其应用效果好且性价比高;淀粉接枝乳液的施胶性能优于氧化淀粉和接枝单体共聚物。     

HDPE三单体固相接枝物的制备及其对PA6/UHMWPE的改性研究

通过马来酸酐(MAH)、苯乙烯(St)和丙烯酸丁酯(BA)多单体固相接枝法对高密度聚乙烯(HDPE)进行接枝改性,制得了增容剂HDPE-g-(MAH/St/BA)。研究发现,接枝率与反应时间、温度、HDPE/单体比及引发剂(BPO)用量有关;HDPE-g-(MAH/St/BA)对聚酰胺6/超高摩尔质量聚乙烯(PA6/UHMWPE)共混物有很好的增容作用,加入HDPE-g-(MAH/St/BA)后,复合材料的力学性能和摩擦磨损性能得到改善。     

以丙烯腈改性淀粉为分散剂的阳离子苯丙乳液的研制

以丙烯腈改性淀粉为分散剂,采用自由基聚合法在淀粉分子链上接枝苯乙烯(St)、丙烯酸丁酯(BA)、甲基丙烯酸二甲基氨基乙酯(DM)和丙烯酰胺(AM)等共聚单体,合成出一种新型的阳离子型淀粉接枝苯丙乳液施胶剂。探讨了K2S2O8/NaHSO3氧化还原型引发剂、共聚单体等对施胶剂施胶效果的影响。结果表明:当w(DM)=2%、w(AM)=0.3%、m(改性淀粉)∶m(单体)=1.0∶1.5、m(St)∶m(BA)=2.3∶1.0、引发剂中m(K2S2O8)∶m(NaHSO3)=1.0∶1.0且氧化剂w(K2S2O8)=0.10%时,施胶剂的施胶效果最佳,并且优于传统苯丙乳液施胶剂。     

温度对杨木木粉表面自由能和表面极性的影响

通过毛细管上升法测定了经过不同温度处理的杨木木粉的表面接触角,依据Washburn方程和Owens-wendt-Kaelble法,求解了经过不同温度处理的杨木木粉的表面自由能及其极性分量和非极性分量。结果表明,杨木木粉的表面自由能为23.43 mN/m,体现分子色散力的非极性分量为4.64 mN/m,在处理时间为2 h的条件下,随着处理温度的上升,杨木木粉的总表面自由能略有下降,体现其分子色散力的非极性表面自由能上升,体现其表面极性值的极性表面自由能下降,并分析了上述结果的原因。     

聚(苯乙烯/马来酸酐/丙烯酸丁酯)的合成

以过氧化苯甲酰为引发剂,在甲苯介质中引发聚合制备苯乙烯(St),马来酸酐(MAH)/丙烯酸丁酯(BA)三元聚合物[P(St/MAH/BA)].探讨了反应时间、温度和单体配比等对P(St/MAH,BA)产量的影响,并对P(St,MAH,BA)的结构和性能进行了表征.结果表明,共聚单体质量比对三元聚合物的产率有决定性的作用.当m(St)/m(MAH)/m(BA)为1.00:1.00:0.78时,聚合物的产率最高,达到70%,相对分子质量为3.5×105,且热稳定性良好.     

CPP/VTES/St接枝共聚物的合成与性能

以二甲苯为溶剂,过氧化苯甲酰(BPO)为引发剂,采用乙烯基三乙氧基硅烷(VTES)和苯乙烯(St)为接枝单体,自由基溶液聚合法改性氯化聚丙烯(CPP),制得接枝共聚胶黏剂。并考察了聚合单体用量及配比、溶剂用量、引发剂用量、反应温度和反应时间对树脂胶黏性能的影响。得到的最佳反应条件为：溶剂与CPP的质量比m(二甲苯)∶m(CPP)=2.5∶1,聚合原料配比m(CPP)∶m (VTES)∶m (St)∶m (BPO) =100∶2.4∶0.6∶0.2,反应温度95 ℃,反应时间3 h。在此条件下制备的共聚物粘接聚丙烯材料和钢的剪切强度分别达3.4 MPa和7.7 MPa。     

水悬浮自搅拌体系中聚丙烯接枝双单体丙烯酸和苯乙烯

以水为分散介质,二甲苯、甲苯为界面剂,过氧化苯甲酰(BPO)为引发剂,在水悬浮自搅拌体系中制备双单体丙烯酸(AA)和苯乙烯(St)接枝聚丙烯共聚物(PP-g-AA/St).重点研究了加料方式、界面剂、分散介质、引发剂、溶胀时间、反应时间、水相阻聚剂、单体组成对接枝反应的影响.得出较佳的工艺条件:反应物料一次加入,投料质量比为二甲苯/水/聚丙烯/单体/过氧化苯甲酰/二氯化锡=2.6/15/10/2/0.015/0.005%,室温溶胀4 h,102℃反应6 h,此条件下双单体接枝率达11.95%,接枝效率高达59.75%.AA与St在物质的量之比为0.846处进行接枝反应时无序共聚副反应严重,傅立叶红外光谱分析结果表明,AA和St接枝到PP大分子链上.     

结合磷阻燃型苯丙共聚乳液胶粘剂的合成及性能研究

以苯乙烯(St)、丙烯酸丁酯(BA)、丙烯酸乙酯(EA)、甲基丙烯酸甲酯(MMA)、丙烯酸(AA)和含磷单体为共聚单体,采用预乳化种子乳液聚合法制备PSA(结合磷型苯丙共聚乳液胶粘剂),并在PSA中添加少量无机阻燃剂APP(聚磷酸铵)制备CPSA(复合型阻燃胶粘剂)。系统研究了含磷单体和APP含量对乳液稳定性、胶膜剥离强度、涂层阻燃性和热性能等影响。结果表明:当m(St+BA+EA+MMA+AA)=40 g、m(St)∶m(BA)∶m(EA)∶m(MMA)∶m(AA)=16∶90∶60∶24∶5、w(含磷单体)=4%和w(APP)=12%(相对于单体总质量而言)时,可制成稳定性、剥离强度和阻燃性能俱佳的CPSA。     

新型表面活性剂对酞菁蓝颜料的表面处理及表面性质的研究

本文自行设计并合成出新型颜料分散剂RSJ,用于酞菁蓝颜料的表面改性处理。分别研究在不同RSJ加量条件下酞菁蓝颜料临界润湿表面张力、表面自由能、流动性以及水相中分散稳定性的改善效果,并从中发现:经RSJ0.5％～3.0％添加量改性处理后,颜料临界润湿表面能γ_c由23mN/m变为34.8mN/m,提高了51％;对水的接触角由82.4°变为47°,减小了47％。表面自由能中的色散成分γ_s~d变化不大,可以认为保持不变,但是γ_s~p却由18.9mN/m变大为27.2mN/m,使得γ_s整体提高13％。此外,流动性提高2.5倍,水中分散稳定性提高了29％。     

Synthesis and structural characterization of methacrylic acid/octadecyl acrylate‐graft‐poly(methylhydrosiloxane) by hydrosilylation

Methylmethacrylate (MMA) and octadecyl acrylate (OA) were grafted to poly(methylhydrosiloxane) (PMHS) by hydrosilylation, respectively, with hexachloroplatinic acid as catalyst, and the former was further hydrolyzed to prepare methacrylic acid (MAA)‐graft‐PMHS under the alkaline condition. Through orthogonal experiment, main factors affecting the graft reaction between OA and PMHS were discussed and arranged in a decreasing order according to their abilities of the effect on the hydrosilylation of OA with PMHS: catalyst dosage, reaction temperature, reaction time, material ratio, and solvent dosage. It was found that the hydrosilylation of OA with PMHS was easier to that of MMA with PMHS. Under optimal conditions, the grafting ratios of MMA with PMHS and OA with PMHS reached about 90 and 95%, respectively. FTIR and ¹H NMR spectra indicated that the hydrosilylation reactions followed the Markovnikov's rule and played a strong preference toward β‐1,2‐addition. The test of contact angle indicated that surface energy of a system was mainly dependent on the polar groups. The surface energy of OA‐graft‐PMHS (35.07 mN/m) was similar to those of PMHS (35.62 mN/m) and polyoctadecyl acrylate (36.57 mN/m), and lower than that of MAA‐graft‐PMHS (43.50 mN/m). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Evaluation of blood cells and proteins spreading on imidic polymers containing alicyclic sequences

A new polyimide containing alicyclic units is investigated in regard to a fully aromatic commercial one in order to assess their hemocompatibility. The rheological, structural, and surface properties of these two polyimides are analyzed by infrared spectroscopy and contact angle measurements. Flow activation energy of polyimide solutions is almost doubled when passing from 8 to 16 %, as an indicative of chain entanglement which enhances film formation ability. The surface tension components are obtained using the Fowkes method, revealing a slightly lower polar component (20.19 mN/m) for the semi-alicyclic polyimide, comparative with the aromatic one (22.52 mN/m). The hemocompatibility is theoretically established from calculation of the spreading work of blood cells and proteins on the polymer surface. The reduced polarizability and high flexibility of the alicyclic units from the new polyimide lead to improved hemocompatibility, as observed from the higher cohesion of blood components with this sample surface, comparative with the aromatic one.     

马来酸酐接枝改性聚丙烯及其在木塑复合材料中的应用

通过双螺杆挤出机聚丙烯熔融挤出接枝马来酸酐制备马来酸酐接枝聚丙烯（PP-g-MAH）;研究了接枝单体马来酸酐（MAH）、引发剂DCP及共单体St等对聚丙烯（PP）熔融接枝MAH的接枝率的影响。将制备的接枝物应用于木塑复合材料中,发现木粉与聚丙烯之间的界面结合有了明显的改善,添加的PP-g-MAH增强了木粉和聚丙烯基体之间的黏合性,使两相结合得更紧密,进而提高了木塑复合材料的力学性能。     

Synthesis and characterization of polyacrylonitrile pregelled starch graft copolymers using ferrous sulfate‐hydrogen peroxide redox initiation system as surface sizing agent

A graft copolymer was synthesized by graft copolymerization of starch with styrene (St) and butyl acrylate (BA), using ferrous sulfate‐hydrogen peroxide redox initiation system. The starch was pregelled in the presence of acrylonitrile (AN) in aqueous alkali at high temperature before graft polymerization. Major factors affecting the polymerization reaction were investigated. It was found that a graft copolymer with higher percentage conversion (PC), graft efficiency (GE) and graft percentage (GP) was obtained by controlling the initiator concentration, concentration, and ratio of monomers and polymerization temperature. The optimum conditions were as follows: H₂O₂ concentration, 12%; monomer concentration, 120%; St/BA ratio, 1 : 1; polymerization temperature, 65°C. Fourier transform infrared spectroscopy and NMR analyses were used to gain information on the structure of the products. It was demonstrated that St, BA, and AN had been successfully grafted onto starch and ? CN had been saponified into ? CONH₂ and ? COO^? to a certain degree when pregelling. Scanning electron microscope micrographs showed the coarse structure and broad network. The graft polymerization took place on the surface of starch granule and led to amorphization of the starch structure. Graft polymer had better thermal stability and was endowed with pseudo‐plasticity. It was observed that the starch graft copolymer offers good properties such as water resistance as surface‐sizing agent. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

汽车工业棉浆滤纸用高效苯丙乳液的合成及应用

以苯乙烯(St)和丙烯酸丁酯(BA)为软单体,N-羟甲基丙酰胺(NMA)和丙烯酸(AA)为交联剂,选用十二烷基硫酸钠(SDS)和脂肪醇聚氧乙烯醚(OS-15)复合体系为乳化剂,过硫酸铵(APS)为引发剂,采用半连续法合成了汽车工业棉浆滤纸用苯丙乳液。通过对涂布后滤纸的检测确定了最佳反应配比为:m(BA)∶m(St)∶m(AA)∶m(NMA)∶m(SDS)∶m(OS-15)∶m(APS)=10.4∶26∶1.6∶2.00∶0.1∶0.3∶0.24。反应温度为85~87℃,上胶量为17.88%。浸渍后滤纸的耐破度可达360 kPa,耐水性约为250 m in,透气度大于480 L.m-2.s-1,挺度大于3.75 mN.m,综合性能良好。     

PP/EVAL/PP-g-MAH动态硫化体系的结构与性能研究

研究了聚丙烯/皂化乙烯-乙酸乙烯共聚物/马来酸酐接枝聚丙烯(PP/EVAL/PP-g-MAH)动态硫化体系的力学性能、相形态、结晶性能和动态机械性能。结果表明:PP-g-MAH能显著改善PP/EVAL动态硫化体系的力学性能和熔体流动速率(MFR)。当PP/EVAL/PP-g-MAH质量比为80/20/8时,材料的冲击强度较不加PP-g-MAH时提高了179.6%,达到74.1 kJ/m2,MFR为13.4 g/10min。PP-g-MAH能有效改善分散相的分散效果和两相相容性,并同时促进PP/EVAL动态硫化体系中PP的α晶和β晶的形成。PP-g-MAH的加入使PP/EVAL动态硫化体系中PP组分的Tg向低温方向移动。     

细乳液聚合法制备含氟丙烯酸酯共聚物乳液的研究

通过细乳液聚合法制备含氟丙烯酸酯共聚物（FPA）乳液,采用红外光谱（ FT-IR）、透射电镜（TEM）、原子力显微镜（AFM）、热重分析仪（ TG）、扫描电镜和表面能谱（ SEM-EDS）等对聚合物进行表征,并考察了乳化剂与助乳化剂的物质的量比,氟单体用量和超声时间对乳液粒径的影响。结果表明,甲基丙烯酸六氟丁酯（ 6FA）、丙烯酸丁酯（ BA）、苯乙烯（ St）3种单体成功聚合,乳化剂与助乳化剂的物质的量比为 1.5∶1,超声时间为 60 min,氟单体用量为 10%时,乳液粒径最小且分布较窄,表面张力从 45.028 mN/m降至 33.399 mN/m,且乳胶膜粗糙度增加,热稳定性提高。     

聚丙烯酸丁酯-丙烯酸/苯乙烯辐射接枝共聚物粘接性能的研究

采用过氧化预辐射法将生产高分子特效膜残留下的废苯乙烯（Ｓｔ）与聚丙烯酸丁酯－丙烯酸（ＰＢＡ－ＡＡ）接枝，制得ＰＢＡ－ＡＡ／Ｓｔ接枝共聚物。比较了辐射法和化学法所制接枝共聚物的粘接性能，考察了Ｓｔ含量、丙烯酸丁酯（ＢＡ）／ＡＡ共聚物特性粘度、ＡＡ用量、ＢＡ和Ｓｔ预辐射剂量对接枝共聚物粘接性能的影响。结果表明，采用辐射法所制接枝共聚物的粘接性能优于化学法所制接枝共聚物的粘接性能；废Ｓｔ比纯Ｓｔ效果好；当Ｓｔ含量为３３％、ＢＡ／ＡＡ共聚物特性粘度适中、ＡＡ用量为５．５份（ＢＡ用量固定为１００份）、ＢＡ预辐射剂量为１６．０ｋＧｙ、Ｓｔ预辐射剂量为３２．０ｋＧｙ时，制得的接枝共聚物的粘接性能最为理想