碳点/水性聚氨酯复合材料的制备及性能

以异氟尔酮二异氰酸酯(IPDI)和聚氧化丙烯二醇(PPG)为原料制备水性聚氨酯,以此为碳源,采用水热法制备碳点,再以IPDI和聚己二酸-1,4-丁二醇酯二醇(PBA)为原料,将不同质量分数的碳点加入反应体系中,制得碳点/水性聚氨酯复合材料。采用FTIR、TEM、SEM、TGA、DSC、UV-Vis、荧光光谱以及力学性能测试等对复合材料结构和性能进行检测和表征。结果显示,复合胶膜的热稳定性、荧光性能、力学强度都因碳点的加入得到提高,当碳点加入质量分数达0.5%时,复合胶膜的量子产率和荧光寿命分别为4.15%和2.43 ns,胶膜的拉伸强度和断裂伸长率分别为36.80 MPa和660%,比未加碳点的样品分别提高了29.7%和33.3%。     

玻纤增强苯乙烯-丙烯腈-环烯烃复合材料的制备和性能

以苯乙烯-丙烯腈-环烯烃树脂（CO-SAN）和玻璃纤维（GF）为原料,以苯乙烯-马来酸酐（SMA）和环氧树脂作为界面相容剂,研究了界面相容剂与玻纤增强CO-SAN复合材料相容性以及对其力学性能、热学性能的影响。结果表明,加入SMA或环氧树脂、GF增强CO-SAN复合材料的力学性能明显提高;SMA与环氧树脂复配有明显的协同效果,同时加入SMA和环氧树脂后的复合材料的性能更加优越,界面粘接性能得到很大的改善,在玻纤加入量为质量分数20%时,其拉伸强度、弯曲强度、冲击强度、维卡软化点温度较未添加界面相容剂时分别提高了59%、25%、33%、17%。     

环氧树脂改性聚乳酸/低熔点尼龙6/蒙脱土纳米复合材料结构与性能

通过熔融共混法制备了环氧树脂改性聚乳酸 (ePLA)/低熔点尼龙6 (LMPA6)/蒙脱土纳米复合材料。XRD和DSC结果表明,结晶度随着有机蒙脱土（OMMT）加入量的增加呈先增加后减小的趋势。流变行为结果表明,ePLA/LMPA6/OMMT纳米复合材料的黏性响应占主导地位,另外,随着OMMT加入量的增加,储能模量和损耗模量也增加。阻隔性能测试结果表明,OMMT的加入能够有效地改善纳米复合材料的阻隔性能。热重结果表明,OMMT的加入能够显著提高纳米复合材料的热稳定性能。TEM测试结果表明,OMMT加入量较少时,OMMT容易在基体中形成均一的纳米结构。力学性能分析表明,随着OMMT质量分数的增加,纳米复合材料的拉伸强度、断裂伸长率和冲击强度均出现先上升后下降的趋势,且当OMMT质量分数为3%时,纳米复合材料的力学性能均达到最大值,与未加OMMT时相比,分别提高了9.7%、37.8%和35.9%。     

改性多壁碳纳米管／聚氨酯乳液的制备与研究

以聚醚多元醇（N-210）、异佛尔酮二异氰酸酯（IPDI）、二羟甲基丙酸（DMPA）、一缩二乙二醇（DEG）为基料,合成了水性聚氨酯预聚体,采用改性多壁碳纳米管（ MWCNTs ）的悬浊液为分散介质得到水性聚氨酯复合乳液。通过TEM、拉力机、TGA对其胶膜的微观结构、力学性能以及热学性能进行测试,结果表明： MWCNTs均匀分散在聚氨酯胶膜中;当MWCNTs质量分数在0.5％时,拉伸强度达到最大值为17.91 MPa,比纯聚氨酯提高了81％;复合材料的断裂伸长率均达到500％以上,最大达到539％,明显高于未加改性碳纳米管的聚氨酯; MWCNTs的加入可明显提高复合材料的耐热性。     

木质纤维和滑石粉混合填充PBS的制备及性能

采用熔融共混法制备了聚丁二酸丁二酯（PBS）/木质纤维/滑石粉复合材料,其中PBS的质量分数固定为70%,其它为木质纤维和滑石粉。流变性能测试结果显示,木质纤维含量越高,复合材料的加工扭矩越大,并在木质纤维质量分数为25%时达到最高值。扫描电子显微镜分析结果表明,木质纤维和滑石粉均匀分散在PBS基体中。X射线衍射测试结果可知,木质纤维的加入降低了基体树脂的结晶度,复合材料中滑石粉的层间距变小。差示扫描量热分析结果显示,滑石粉有利于复合材料的冷结晶,PBS/木质纤维/滑石粉复合材料的熔融峰和结晶峰比PBS/木质纤维复合材料和PBS/滑石粉复合材料的尖锐。力学性能测试结果显示,加入木质纤维可以提高复合材料的力学性能,当木质纤维质量分数为25%时,复合材料的力学性能达到最佳,此时复合材料的拉伸强度为11.1 MPa,断裂伸长率和缺口冲击强度达到最大值,分别为93.3%,3.56 kJ/m²。土壤降解数据表明,木质纤维的加入显著提高了复合材料的降解速率,说明合适用量的木质纤维和滑石粉具有协同效应,能使PBS/木质纤维/滑石粉复合材料拥有更好的降解性能。     

羟基硅油改性水性聚氨酯的制备与性能研究

以羟基硅油（PDMS）、二苯基甲烷二异氰酸酯（MDI）、聚醚多元醇为主要原料,合成了有机硅改性的水性聚氨酯（WPU）材料,探讨了PDMS用量对WPU乳液和胶膜性能的影响,并采用FT—IR和DSC对其进行了表征。结果表明,随着PDMS加入量的增加,乳液粒径增大,粘度升高,胶膜的吸水率降低,力学性能和热稳定性提高。当PDMS质量分数为11．8％时,制备的有机硅改性聚氨酯材料性能最佳,其吸水率下降至5．6％,拉伸强度达到14．74MPa,断裂伸长率为462％,胶膜的初始分解温度提高了36℃。     

氧化石墨烯/聚乙醇纤维复合材料的制备与性能

为解决复合材料在长期使用时出现力学性能与耐久性能降低的问题，将氧化石墨烯（GO）与聚乙烯醇纤维（PVA纤维）掺入到复合材料中，对其力学性能与耐久性能进行探索研究。结果表明：1%～5%的PVA纤维、0.05%（质量分数）～0.075%（质量分数）的GO，对复合材料试件各龄期的力学强度提升程度最大；1%～2%的PVA纤维，对复合材料抗干缩性能与抗冻融性能改善效果最好；0.05%（质量分数）～0.075%（质量分数）的GO对复合材料抗冻融性能改善效果最好，但对抗干缩性的影响随着掺量的增加呈先小幅提升后大幅削弱的趋势。     

POM/GF-MWCNTs复合材料的制备及其性能研究

将经γ氨丙基三乙氧基硅烷（KH550）处理后的多壁碳纳米管（MWCNTs）接枝到玻璃纤维（GF）表面,制成GF-MWCNTs复合填料,通过双螺杆挤出机熔融共混制备出聚甲醛（POM）/GF-MWCNTs复合材料,并对其力学性能、热性能及电性能进行了测试。结果表明,GF-MWCNTs添加量较低时,复合材料的拉伸强度和缺口冲击强度都有所提高,且分别在3 %（质量分数,下同）和1 %时达到最大值,之后则随着填料含量的增加而不断降低;当GF-MWCNTs的添加量达到10 %时,复合材料的拉伸强度和缺口冲击强度已然低于纯POM;加入GF-MWCNTs提高了复合材料的热稳定性,使POM的结晶温度和结晶度提高;GF-MWCNTs能降低复合材料的体积电阻率,但由于未在POM基体中形成逾渗网络,复合材料导电性提高并不明显。     

EP/BMI树脂基碳纤维复合材料的制备与性能表征

以环氧树脂(EP)、双马来酰亚胺(BMI)、4,4’-二氨基二苯砜(DDS)和短切碳纤维(SCF)等为主要原料制备了EP/BMI/DDS/SCF复合材料,并研究了SCF添加量对复合材料力学性能和热性能的影响。结果表明,当SCF添加量为0.25 %(质量分数,下同)时,EP/BMI/DDS/SCF复合材料的力学性能提高最大,其拉伸强度、弯曲强度、弯曲模量和缺口冲击强度比未添加SCF时的EP/BMI/DDS复合材料分别提高了48.52 %、32.15 %、25.77 %以及150.91 %;此外,SCF的加入有助于提高复合材料的热性能。     

聚乳酸/乙烯-醋酸乙烯酯共聚物/碳酸钙复合材料的性能研究

采用熔融共混法制备了聚乳酸/乙烯-醋酸乙烯酯共聚物/碳酸钙（PLA/EVA/CaCO3）复合材料,利用差示扫描量热仪、X射线衍射仪、偏光显微镜、扫描电子显微镜、力学性能测试和热变形温度测试等手段,研究了EVA和CaCO3对复合材料的结晶性能、断面形貌、力学性能和耐热性能的影响。结果表明,EVA 具有增韧作用,但降低了复合材料的强度和耐热性;而CaCO3可以提高复合材料的强度、韧性、结晶性能和耐热性能;CaCO3与EVA的加入对PLA有协同增韧作用,且不改变PLA的晶型;当PLA/EVA=90/10,加入10 %（质量分数,下同）的CaCO3时,复合材料有最佳的综合性能。     

Green synthesis of nitrogen-doped carbon dots from ginkgo fruits and the application in cell imaging

In the report, microwave-assisted and hydrothermal methods were adopted respectively to produce nitrogen doped carbon dots (N-CDs) using ginkgo fruits as the sole carbon source without additional surface passivation agents. The differences between these two N-CDs were compared in luminescence properties, particle sizes and morphologies. The TEM images showed that both microwave-assisted N-CDs (M-N-CDs) and hydrothermal N-CDs (H-N-CDs) were well dispersed, and the morphology of H-N-CDs was more uniform. The fluorescence results indicated the H-N-CDs possessed better fluorescence emission characteristic. Thus, the H-N-CDs with better luminescence properties were characterized by FT-IR, XPS, fluorescence and UV–Vis spectroscopy. Also, the stability and cytotoxicity of H-N-CDs synthesized by ginkgo fruits as the fluorescent probes were studied. Eventually, the H-N-CDs were applied in cell imaging using HeLa cells and KYSE410 cells as the cell models.     

Fabrication,characterization and response surface method optimization for quantum efficiency of fluorescent nitrogen-doped carbon dots obtained from carboxymethylcellulose of oil palms empty fruit bunch

Bio based nitrogen doped carbon dots (N-CDs) were obtained from empty fruit bunch carboxymethylcellulose and ethylenediamine (EDA) through one-pot hydrothermal carbonization route. The optimum as-formed NCDs were thoroughly characterized via Transmission electron microscopy (TEM), high-resolution TEM (HRTEM), Fourier transform infrared (FTIR), X-ray photoelectron spectra (XPS), UV-vis spectra (UV-Vis) and Fluorescence spectra (PL). Response surface methodology was statistically used to assess three independent variables that have major influence on the fluorescence quantum yield (QY), including temperature (230-270 ℃), time (2-6 h) and EDA mass (10%-23.3%). Based on analysis of variance (ANOVA) results, synthesis temperature was found to be the most influential factor on the QY, followed by time and EDA mass. Higher temperature, long synthesis time and high amount of EDA were satisfactorily enough for efficient carbonization conversion rate and obtaining highest QY of N-CDs. The obtained quadratic model (R²=0.9991) shows a good correlation between the experimental data and predicted values. The optimum synthetic parameters are of 270 ℃ temperature, 6 h reaction time and 23.3% of EDA mass. The optimized as-made N-CDs exhibited blue photoluminescence with both excitation dependent/independent phenomena and high nitrogen content. The maximum emission intensity was 426 nm at a maximum excitation wavelength of 320 nm, with a QY of up to 22.9%. XPS and FTIR data confirmed the existence of polar containing groups, such as carbonyl, carboxyl, hydroxyl and amino groups over the surface of N-CDs whereas nitrogen species in the form of (pyridinic and graphitic-N) were introduced in the aromatic carbon domains, which imparts the hydrophilic and photostability of N-CDs. Taking into account the low-cost and sustainable production of N-CDs, this method considered a feasible route for converting low quality waste into value-added nanomaterials and utilizing for different functionalization processes and analytical applications.     

Preparation and properties of T300 carbon fiber‐reinforced thermoplastic polyimide composites

In this study, a series of T300 carbon fiber‐reinforced polyimide (CFRPI) composites were prepared by laminating premolding polyimide (PI) films with unidirectional carbon fiber (CF) layers. On the basis of PI systems design, the effect of CF volume fraction, processing conditions, and PI molecular structure on the properties of CFRPI composites was studied in detail. In addition, two kinds of nano‐particles, including carbon nano‐tube (CNT) and SiO₂ were filled into the premolding PI films with different concentrations. And the effect of nano‐particles on the properties of CFRPI composites was also investigated. The surface characteristic of T300 CF was measured by X‐ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The properties of premolding PI film and CFRPI composites were measured by dynamic mechanical analysis (DMTA), SANS testing machine, scanning electron microscopy (SEM), and so forth. These experimental results showed that the properties of CFRPI composites were mainly affected by the premolding PI film and molding condition. The change of CF volume fraction from 55% to 65% took little effect on the mechanical properties of CFRPI composites. In addition, the incorporation of nano‐particle SiO₂ could further improve the properties of CFRPI composites, but CNT hardly improved the properties of CFRPI composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 646–654, 2006     

短切碳纤维对聚苯腈/碳纤维复合材料性能的影响

利用碳纤维（CF）增强聚苯腈（PN）树脂制备一系列PN/CF复合材料,利用万能试验机和动态热机械分析仪（DMA）,研究短CF含量、长度与偶联剂种类对PN树脂力学性能的影响。结果表明,采用苯基三乙氧基硅烷作为偶联剂时力学性能和热稳定性达到最佳水平,相较于未经偶联剂改性PN/CF复合材料的储能模量提高了22.2%,热失重5%温度（Td5%）提高了33.1%;随着CF掺杂量的增加,材料力学性能呈现先增大后减小趋势,在0.3%（质量分数,下同）时获得了最优异力学性能,相较于PN树脂,其弯曲强度提高了38.4%,弯曲模量提升了97.7%;CF长度为6 mm时材料的弯曲强度和储能模量优于CF长度为3 mm时的材料。     

炭纤维增强中间相炭微球制备炭/炭复合材料

以中间相炭微球为炭源,沥青基磨切炭纤维为同质增强相,采用冷模压成型和气氛低温烧结制备出高性能炭/炭复合材料。研究了炭纤维表面处理对界面结合强度的作用机制和改善效果,分析了不同球磨时间下原始粉料的微观形貌。结果表明：炭纤维的添加有利于坯体各向均匀收缩,降低了总体积收缩率,使得复合材料密度下降;同时大幅度提升了复合材料的机械强度;添加10%（质量分数）炭纤维时弯曲强度最高,达到123.5MPa。     

聚酰亚胺/纳米炭黑复合材料的性能研究

采用原位聚合法制备聚酰亚胺/纳米炭黑复合材料,采用傅里叶变换红外光谱仪、万能试验机和摩擦磨损试验机研究了纳米炭黑添加量对复合材料亚胺化程度﹑力学性能﹑摩擦磨损性能的影响。结果表明,适量纳米炭黑的加入能够有效改善复合材料的摩擦学性能和力学性能;当纳米炭黑含量为固含量的28%时,复合物材料的摩擦学性能较好,复合材料表面犁沟变浅,表面变平整。     

混炼方式对螺旋纳米碳纤维增强天然橡胶复合材料力学性能的影响

采用干法和湿法两种混炼工艺制备了螺旋纳米碳纤维(HCNFs)/炭黑(CB)/天然橡胶(NR)复合材料,通过扫描电镜、拉伸试验机和应变扫描仪分别对所制备复合材料的界面形貌、力学性能和Payne效应进行了测试分析,考察了混炼方式对复合材料宏观力学性能及Payne效应的影响。结果表明,与纯CB填料相比,在干湿两种混炼方式下,添加适量的HCNFs(1～6份)能提高HCNFs/CB/NR复合材料的300%定伸应力、扯断伸长率、拉伸强度和硬度。与干法混炼相比,湿法混炼能明显增强HCNFs/CB/NR复合材料的Payne效应,并提升在HCNFs高添加量(2～6份)条件下的拉伸强度和扯断伸长率,这主要源于湿法混炼能够有效改善HCNFs在橡胶基质中的分散性。     

油茶果壳对PE-HD力学性能的影响

以废弃油茶果壳和高密度聚乙烯(PE-HD)为原料,采用挤出成型工艺制备了PE-HD/油茶果壳复合材料。采用热重法测试了油茶果壳的热稳定性,研究了油茶果壳平均粒径、添加量及相容剂马来酸酐接枝聚乙烯(MAPE)添加量对复合材料力学性能的影响。结果表明,油茶果壳初始热解温度为211℃,热解残炭率达31.35%。随着油茶果壳平均粒径减小、油茶果壳和MAPE添加量增加,复合材料的拉伸、弯曲和缺口冲击强度均呈现先增大后减小的趋势。当油茶果壳平均粒径为380μm,添加量为40份,MAPE添加量为3份时,复合材料的力学性能最佳。     

Mechanical and electrical properties of poly(vinylidene fluoride–tetrafluoroethylene–propylene)/Super‐S carbon black swelled in liquid solvent as an electrode binder for lithium‐ion batteries

The mechanical and electrical properties of poly(vinylidene fluoride–tetrafluoroethylene–propylene) (PVDF–TFE–P) and carbon black–filled PVDF–TFE–P composites were investigated. The carbon black was used for its electrolyte absorption properties in addition to boosting the conductivity. This elastomeric binder system may have application to tin‐ or silicon‐based electrode materials for Li‐ion batteries, which undergo huge volumetric changes during charge/discharge cycling. The mechanical and electrical properties were measured while film samples were immersed in a liquid solvent (ethylene carbonate : diethyl carbonate 1 : 2) commonly used in the battery electrolyte. Uncrosslinked PVDF–TFE–P uptakes about 140% solvent by mass and swells significantly. The amount of solvent absorbed can be reduced and the mechanical properties improved by crosslinking the polymer. Two crosslinking recipes, based on bisphenol and triethylenetetramine (TETA), were investigated carefully. Compared to the bisphenol‐based crosslinking recipe, the proposed TETA‐based crosslinking recipe gave films with a higher degree of crosslinking and better mechanical properties. The TETA‐crosslinked composites had very good mechanical and electrical reversibility even during cyclic deformation to 100% strain. The cycling results of amorphous Si_0.64Sn_0.36 electrodes show that the capacity retention of the electrodes can be significantly improved by using the proposed elastomeric binder. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2958–2965, 2004