长链硅烷改性杨木纤维的制备及其表征

Preparation and Characterization of Long-chain Silanes Modified Poplar Wood Fiber

分别以十六烷基三甲氧基硅烷(HDS)和1H,1H,2H,2H-全氟十七烷三甲基氧硅烷(FDS)为改性剂、乙醇/水溶液为分散介质,采用浸渍法和喷雾法对杨木纤维(PWF)表面改性,制得HDS浸渍改性杨木纤维(HPWF)、FDS浸渍改性杨木纤维(FPWF1)和FDS喷雾改性杨木纤维(FPWF2)。考察了溶剂配比、硅烷用量、硅烷水解温度和时间、反应温度及反应时间等因素对PWF表面改性效果的影响,并通过红外光谱(FT-IR)、接触角测量、X射线衍射(XRD)、X射线能谱(EDS)及扫描电镜(SEM)等方法表征了改性前后PWF的结构与表面性能,结果表明:在乙醇质量分数60%乙醇/水溶液中以HDS与PWF活性羟基物质的量比0.4∶1、HDS于60℃水解1 h,再与PWF于60℃反应1 h,所得HPWF的表面接触角达139°;在乙醇质量分数50%乙醇/水溶液中以FDS与PWF活性羟基物质的量比0.16∶1、FDS于60℃水解1 h,再与PWF于60℃反应1 h,所得FPWF1的表面接触角达141°;FDS与PWF活性羟基物质的量比0.008∶1,经喷雾搅拌使纤维表面润湿后于120℃活化反应1.5 h,所得FPWF2的表面接触角达138°。与浸渍法相比,喷雾法具有硅烷用量小、工艺简单、清洁高效等特点。此外,改性后杨木纤维的结晶度提高(由62.1%提高到67.7%~69.7%),表面变得粗糙,比表面积增加,表面极性降低,疏水性能显著提高,有利于改善与疏水性基体树脂的界面相容性与粘结作用。

Three kinds of modified poplar wood fibers(PWF)named hexadecyltrimethoxysilane(HDS)impregnated modified poplar fiber(HPWF),1H,1H,2H,2H-perfluorodecyltrimethoxysilane(FDS)impregnated modified poplar fiber(FPWF1)and FDS spray modified poplar fiber(FPWF2)were obtained by respectively using HDS and FDS as modifiers and ethanol-water solution as dispersing media by impregnation and spray methods.The effects of solvent ratios,dosage of silanes,hydrolysis temperature and time of silanes,reaction temperature and time on the surface modification of PWF were studied.The chemical structures and surface properties of unmodified and modified PWF were investigated by Fourier transform infrared(FT-IR)spectroscopy,contact angle measurement,X-ray diffraction(XRD),X-ray energy dispersive spectrometer(EDS)and scanning electron microscope(SEM).HPWF was treated with HDS(hydrolyzed at 60℃for 1 h)at 60℃for 1 h in ethanol/water solution.The results showed that when the molar ratio of HDS to active hydroxyl of PWF was 0.4∶1 with ethanol mass fraction of 60%,the surface contact angle of HPWF was up to 139°;when the molar ratio of FDS to active hydroxyl of PWF was 0.16∶1 with ethanol mass fraction of 50%,the surface contact angle of FPWF1 was up to 141°.Specially,the surface contact angle of FPWF2 was up to 138°when the fiber was wetted at the molar ratio of FDS to active hydroxyl of PWF 0.008∶1,and then activated at 120℃for 1.5 h.Compared with the impregnation method,the spray method had the advantages of small dosage of silane,simple process,cleanliness and high efficiency.In addition,the modified fibers had the properties of higher crystallinity(from 62.1%to 67.7%-69.7%),rougher surface,bigger specific surface area,lower surface polarity,and higher hydrophobicity,which were conducive to improving the interfacial compatibility and bonding with hydrophobic resin matrix.