炭黑/水性聚氨酯复合材料的制备与气敏性能研究

在环境友好的水性聚氨酯（WPU）基体乳化前加入导电填料炭黑（CB），制备了CB／WPU气敏复合材料，并研究了其气敏响应和吸收行为。研究表明，CB／WPU复合材料对有机溶剂蒸气的吸收量与气敏响应度之间没有定量关系，气敏响应时间要比吸收平衡时间小得多，当吸收尚未达到平衡时，复合材料的电阻早已达到最大值。气敏响应度的大小与有机溶剂的溶度参数尤其极性分量有关，基体和溶剂的总溶度参数相差越小，气敏响应度越大。     

聚乙二醇接枝炭黑纳米导电复合材料气敏性研究

以聚乙二醇接枝炭黑(PEG—g—CB)为导电粒子，不同相对分子质量的聚乙二醇(PEG)为基体，制备了PEG／PEG—g—CB纳米导电高分子复合材料，并研究了其气敏性能。结果发现，该复合材料在PEG极性溶剂蒸汽中电阻响应快，而在非极性溶剂蒸气中电阻几乎不改变；PEG的晶相结构以及CB的接枝与否对响应重复性有很大影响。     

炭黑改性及对水性聚氨酯涂膜导电性的影响

采用原位乳液合成法,以炭黑（CB）为芯材、聚氨酯(PU)为壁材,制备表面均匀包覆聚氨酯的改性炭黑粒子（CB-PU）,通过FTIR、TG、SEM、EDS等表征了改性前后粒子的结构和形态;对粒子进行分散性试验,结果表明,CB-PU在水中的均匀分散性与稳定性相比CB明显提高;将改性前后粒子与水性聚氨酯（WPU）涂料复合得到不同CB含量的导电涂料（CB/WPU、CB-PU/WPU）,经涂覆、烘干得到导电膜材。研究结果显示,由于均匀包覆的壳层聚氨酯的亲水性,CB-PU能较为均匀地分散在WPU涂膜中;同时,由于CB-PU在涂膜中分散性的提高,极大地增大了涂料中导电粒子的网络密度和网络强度,CB-PU/WPU涂膜的导电性能显著提高;当保持体积电阻率约为3.3×103 Ω•cm时,CB质量分数由CB /WPU涂膜中的12 wt%下降到CB-PU/WPU 涂膜中的6 wt%;研究表明,通过在CB表面均匀包覆基体树脂层,可有效改进CB在基体中的分散性以及促进其导电网络形成。涂膜力学测试表明,添加改性后CB的涂膜断裂伸长较CB更优异,而强度有所下降。     

PVA/CB复合材料气敏性能研究

以聚乙烯醇为基体,以炭黑为导电性添加剂,通过共混法制得常温响应聚乙烯醇/炭黑(PVA/CB)气敏导电薄膜,研究了复合薄膜材料在乙醇蒸气中的室温气敏性能。研究结果表明,PVA/CB复合材料的气敏性能跟炭黑的分散性、含量、材料的厚度等因素有关。炭黑分散性越好,气敏性越好;炭黑含量存在一最佳值;材料厚度增加,阻碍气体的扩散导致气敏性降低。     

改性炭黑对水性聚氨酯涂膜导电性的影响

采用原位乳液合成法,以炭黑(CB)为芯材、聚氨酯(PU)为壁材,制备聚氨酯改性的炭黑粒子(CB-PU)。通过FTIR、TG、SEM、EDS等对样品进行了表征。结果表明,炭黑粒子表面成功包覆了聚氨酯层,改性后粒子粒径约为50~250 nm,改性粒子中聚氨酯质量分数为58.7%,CB-PU在水中的均匀分散性与稳定性相比CB明显提高。将改性前、后炭黑粒子与水性聚氨酯(WPU)涂料复合得到不同CB或CB-PU含量的导电涂料(CB/WPU、CB-PU/WPU),经涂覆、烘干得到导电膜材。结果显示,由于CB-PU在涂膜中分散性的提高,增大了涂料中导电粒子的网络密度和网络强度,CB-PU/WPU涂膜的导电性能显著提高;当保持体积电阻率约为3.3×103?·cm时,涂膜中CB的含量由CB/WPU中的12%(以PU的质量为基准,下同)下降到CB-PU/WPU中的6%。涂膜力学测试表明,纯WPU涂膜的断裂伸长率为487.5%,CB-PU/WPU涂膜为485.5%,而CB/WPU涂膜则下降到335.3%。     

3D打印炭黑/水性聚氨酯导电复合材料的制备及性能

采用硅烷偶联剂KH550对炭黑（CB）进行共价键功能化改性,并通过FTIR、DLS和SEM对改性前后的炭黑进行考察。结果表明经过KH550改性得到的炭黑,粒径约为620nm,且分散均匀。通过溶液共混法和流延浇铸法制备了CB/WPU与KH550/CB/WPU导电复合材料。研究对比发现,由于KH550/CB在WPU基体中分散性更好,使导电粒子之间接触更加紧密。当添加量为3%时,其电导率为1.79×10-3 S/m,较CB/WPU复合材料增加了10倍;力学测试显示含量为2%时,其拉伸强度较CB/WPU复合材料增加了175%。并在此基础上利用直写式3D打印,探讨不同的填充图案和填充率对KH550/CB/WPU复合材料导电性能的影响。结果显示选择线型填充、填充率为80%时,导电性能较好,其电导率达到2.66×10-3 S/m。     

3D打印炭黑/水性聚氨酯导电复合材料的制备及性能

采用硅烷偶联剂KH550对炭黑(CB)进行了改性,得到了KH550改性的CB(KH550/CB),通过FTIR、DLS和SEM对CB和KH550/CB进行了表征,采用共混法和流延浇铸法分别制备了CB/水性聚氨酯(CB/WPU)复合材料与KH550/CB/水性聚氨酯(KH550/CB/WPU)复合材料。利用直写式3D打印,探讨了不同的填充图案和填充率对KH550/CB/WPU复合材料性能的影响。结果表明,KH550/CB粒径约为620 nm,分散均匀,在WPU基体中分散性更好,导电粒子之间连接得更紧密。当CB与KH550/CB含量(以WPU质量为基准,下同)均为3%时,KH550/CB/WPU复合材料的电导率为1.79×10^–3 S/m,比CB/WPU复合材料的电导率增加了14倍;CB与KH550/CB含量均为2%时,KH550/CB/WPU复合材料的拉伸强度比CB/WPU复合材料增加了175%。选择填充图案为线形、填充率为80%时,KH550/CB/WPU导电性能较好,电导率达到2.66×10^–3 S/m,与其他非3D打印产品相比,其导电性能...     

CB/PLA与CB/RF/PLA导电高分子复合材料气敏性能对比

通过熔融共混法制备了炭黑(CB聚乳酸(PLA和CB/苎麻纤维(RFPLA导电高分子复合材料(CPCs。扫描电镜(SEM观察发现导电填料在CB/PLA中分散良好。通过预混合的方法,可以先使CB和PLA良好接触,随后的熔融加工过程中,CB/RF/PLA中CB粒子分布在RF附近,这种纤维搭接的CPCs逾渗值比CB/PLA更低。气敏测试对比研究发现,含RF的导电复合材料在不良溶剂中响应度高,重复性好;在良溶剂中,响应时间长,气敏稳定性好。为制备逾渗值低,气敏性能优良的可降解CPCs提供了新思路。     

聚甲基丙烯酸甲酯／聚乙二醇／炭黑导电复合材料的制备与导电性能研究

采用原位聚合法制备了聚甲基丙烯酸甲酯／聚乙二醇／炭黑（PMMA/PEG/CB）导电复合材料，研究了其导电性能及其对有机蒸气的电阻响应性能。结果表明，当MMA／PEG质量比为8／1时，原位聚合反应时间为20～30min，单体转化率可达94％以上；复合材料的导电性能显著增强，当CB质量分数为8．5％时，复合材料的电阻率为1．3Ω·cm；该复合材料在较大CB含量范围内对有机蒸气产生显著的电阻响应，对PMMA的良溶剂（如丙酮、乙酸乙酯、氯仿等）蒸气的电阻响应程度可达104，而对非溶剂甲醇蒸气的仅为140。     

超声辐射对PVA/CB导电复合材料气敏性能的影响

以聚乙烯醇(PVA)为基体,填充各种类型炭黑导电粒子,制备了导电复合薄膜。研究了超声作用下导电复合薄膜在不同溶剂蒸气中的气敏性能。考察了PVA与炭黑的比例、炭黑种类、超声时间、超声功率等条件对导电薄膜响应性能与响应稳定性的影响,并对这种导电复合薄膜产生气敏响应性的机理作了分析。结果表明,以PVA/乙炔炭黑组成的导电复合薄膜具有较强气敏响应性。当将其置于丙酮、正丁醇、乙醇、水极性溶剂中,电阻急剧提高102~103倍,表现为正蒸气系数效应(PVC);随炭黑含量提高,复合材料薄膜室温电阻下降,对溶剂蒸气的响应强度提高;超声时间、功率对导电粒子分散行为及复合材料的气敏性有影响,随超声时间延长及功率增大,接枝改性效果明显,导电薄膜的响应性及重复稳定性提高。     

Grafting modification of carbon black by trapping macroradicals formed by sonochemical degradation

Polymers were grafted onto the surface of carbon black (CB) by the trapping of macroradicals formed by sonochemical degradation of a polymer solution. Long chain radicals of poly(vinyl alcohol) (PVA) formed by sonochemical degradation were successfully trapped by CB and grafted onto its surface. Results showed the method to be suitable for all kinds of CB, even for furnace black with few functional groups. The crushing effect of the ultrasonic forces caused the PVA grafted CB to have a much smaller aggregate particle size and narrower particle size distribution than that of the original CB, as indicated by dynamic light scattering. The PVA grafted CB could be well dispersed in water and a polymer matrix. The compatibility between CB and polymer was significantly improved.     

硅烷偶联剂封端改性水性聚氨酯的研究

以聚醚多元醇(GE210)、异佛尔酮二异氰酸酯(IPDI)和α,α-二羟甲基丙酸(DMPA)为原料合成了基础聚氨酯(PU)预聚体,然后以1,4-丁二醇进一步扩链制得了水性聚氨酯(WPU)乳液,最后以偶联剂γ-氨丙基三甲氧基硅烷对PU分子进行封端,得到了稳定的改性PU乳液。通过对偶联剂的用量和封端条件等研究,确定了适合硅烷改性WPU的方式。实验结果表明,当w(硅烷偶联剂)=4%～5%时(占树脂的质量分数),硅烷偶联剂封端改性WPU乳液具有较低的表面张力,其胶膜的力学性能和耐水耐溶剂性能均相当优异。     

The polydopamine-assisted heparin anchor enhances the hydrophilicity,hemocompatibility, and biocompatibility of polyurethane

Surface heparinization is an effective solution to resolve low endothelialization, poor anticoagulation, and hemocompatibility of polyurethane (PU) used as materials of small-diameter vascular grafts. Here, the effects of polydopamine (PDA) and poly (acrylic acid) (PAA) as crosslinking agents on the surface heparinization were explored. The PU membranes grafted with heparin (Hep) via dopamine (PU/PDA-Hep) showed better hydrophilicity and stability, compared to heparinized PU membranes via acrylic acid (PU/PAA-Hep). The results of X-ray photoelectron spectroscopy demonstrated that heparin was successfully grafted onto the PU surface and the grafting efficiency was high when PDA as a cross-linking agent. The grafted heparin aggregated and formed nanoparticles, and increased the surface roughness of PU membranes. The heparinized membranes demonstrated good anti-adhesion of bovine serum albumin and fibrin protein. In addition, no activated platelets or educts on heparinized PU were found by platelet adhesion tests, implying that heparin-immobilized surfaces had good hemocompatibility. Moreover, the in vitro cytocompatibility assessment showed that the PU/PDA-Hep significantly improved the proliferation of L929 cells and was superior to PU/AA-Hep. These results demonstrated that PDA-assisted surface heparinization was an effective method to improve the anticoagulant and biocompatibility of PU small-diameter vascular materials and could be extended to other implantable materials.     

多壁碳纳米管在聚氨酯基涂覆材料中分散性能的研究

采用混合酸对多壁碳纳米管（MWCNTs）进行处理,得到具有反应性基团的功能化多壁碳纳米管（O?MWCNTs）;以聚乙二醇（PEG1000）和异佛尔酮二异氰酸酯（IPDI）为主要原料反应生成聚氨酯（PU）预聚体,然后通过原位复合法制备了PU/MWCNTs、PU/O?MWCNTs复合乳液;通过透射电子显微镜（TEM）、扫描电子显微镜（SEM）、X射线光电子能谱仪（XPS）及红外光谱仪（FTIR） 等仪器表征分析了MWCNTs和O?MWCNTs的微观结构、表面形貌和分散性能,并通过FTIR对PU、MWCNTs/ PU、PU/O?MWCNTs进行了结构特征分析。结果表明,混合酸处理使MWCNTs侧壁引入了约自身质量10.2 %的含氧官能团,极大地提高了MWCNTs在PU基体中的分散性;O?MWCNTs在PU预聚体形成之后加入时,会与PU链嵌段或者接枝,更利于分散;PU/O?MWCNTs复合乳液外观细腻呈黑灰色,静置36 h后O?MWCNTs仍呈现良好的分散性。     

多壁碳纳米管的表面改性及其在水性聚氨酯体系中的应用

采用自制的硅烷类改性剂(s-PEG)对经过酸氧化的多壁碳纳米管(MWNTs)进行表面改性处理,并通过共混法制备了MWNTs/水性聚氨酯(WPU)复合材料,研究了MWNTs的添加对复合材料性能的影响.结果表明,改性剂s-PEG成功地包覆于MWNTs表面,形成了s-PEG壳层,包覆率约为25％.改性MWNTs (s-PEG-MWNTs)的添加可以明显改善WPU复合材料的拉伸性能,当s-PEG-MWNTs的添加量为1％时,复合材料的拉伸强度和断裂伸长率比未添加MWNTs的材料分别提高了597％和152％.s-PEG-MWNTs在WPU基体中达到了良好的分散效果.此外,s-PEG-MWNTs的添加显著地增强了复合材料的导电性能.     

Synthesis of anionic water‐borne polyurethane with the covalent bond of a reactive dye

We successfully synthesized an anionic water‐borne polyurethane (PU) capable of reacting with a reactive dye to form a covalent bond with the dye molecule. The anionic water‐borne PU was synthesized and grafted with the reactive dye to form a dyed PU. First, the PU prepolymer was synthesized from 4,4′‐methylene bis(isocyanatocyclohexane), poly(tetramethylene glycol), 2,2′‐bis(hydroxymethyl) propionic acid (as an anionic center), and triethyleneamide (as a neutralizer). Then, pure water was added to emulsify and disperse the prepolymer to form an anionic water‐borne PU prepolymer. Finally, the extender N‐(2‐hydroxyethyl) ethylene diamine was used to extend the anionic water‐borne prepolymer to form a PU polymer with hydroxyl groups that could further react with the reactive dye molecule. With respect to the heating properties, the dyed PU polymers exhibited higher glass‐transition temperatures of the hard segment than those without dye molecules. However, neither the glass‐transition temperature of the soft segment nor the melting temperature of the soft segment varied in the presence of dye molecules, but they were changed with various chain lengths of the soft segment. As for the mechanical properties, the modulus and strength of the dyed PU polymers decreased because of the bulkiness of their dye molecules, but the breaking elongation increased. Moreover, the inherent viscosity decreased in the presence of the dye molecules. As for the dyeing properties, the percentage of dye grafting was greater than 90%. The dye‐grafted PU exhibited a lower percentage of migration than PU extended with ethylene diamine (without hydroxy groups) and also showed a higher grade of colorfastness to light. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 797–805, 2002; DOI 10.1002/app.10336     

改性水性聚氨酯汽车内饰胶的合成

采用丙酮法,并以聚醚二元醇(N220)、甲苯二异氰酸酯(TDI-80)、1,4-丁二醇(BDO)和二羟甲基丙酸(DMPA)等为原料,制备了聚氨酯(PU)预聚体;然后以丙烯酸酯为改性剂合成出水性聚氨酯(WPU)乳液。实验结果表明,当w(丙烯酸酯单体)=25%、w(DMPA)=3.8%时,可得到高性能的改性WPU乳液;由该乳液制得的胶粘剂可以满足汽车内饰材料的粘接要求。     

催化剂对复合薄膜用水性聚氨酯胶粘剂性能的影响

采用丙酮法制备了复合薄膜用的水性聚氨酯(WPU)乳液胶粘剂,研究了催化剂用量对WPU反应速率及其性能的影响。研究结果表明,适量的催化剂能明显加快聚氨酯(PU)预聚体的反应速率;当催化剂质量分数为0.1%时,WPU乳液的粘度和复合薄膜的T型剥离强度最大,但WPU胶膜的玻璃化转变温度(Tg)降低,由未加催化剂时的-25.5℃降低到-29.1℃。     

温度和锡催化剂对WPU反应速率影响及乳化反应条件选择

以2,4-甲苯二异氰酸酯(TDI)、聚乙二醇(PEG)及N-甲基二乙醇胺(MDEA)等为原料,制备出一种亲水性阳离子型水性聚氨酯(WPU)乳液。通过跟踪测定预聚体中-NCO含量,分析了温度和锡催化剂用量对PU(聚氨酯)预聚反应速率的影响,并对后续乳化反应条件进行了选择。结果表明:PU预聚反应速率随温度升高和催化剂用量增加而增大;当温度为60℃、w(催化剂)=1.0%时,预聚反应迅速且平稳。采用低温乳化、先中和后乳化、将中间体加入水中以及低搅拌速率等方法,可以得到分散性好、气泡量低且性能稳定的WPU乳液。