长链酰胺化纳米纤维素增强聚乳酸复合材料

以纳米纤维素(NCC)为原料,先采用四甲基哌啶氮氧化物(TEMPO)氧化制备氧化纳米纤维素(TONC),再与不同链长脂肪胺在催化剂作用下发生反应,得到脂肪胺改性纳米纤维素,当脂肪胺为十二胺(DOA)、十四胺(TEA)、十六胺(HEA)、十八胺(OCA)时,分别制得DOATONC、TEATONC、HEATONC和OCATONC。傅里叶变换红外光谱(FT-IR)、X射线衍射(XRD)和元素分析表明:脂肪链接枝成功,改性后纳米纤维素的晶形没有发生改变,为原有Ⅰ型晶型;接触角和分散性测试表明:随着脂肪链的增长,改性纳米纤维素表面的亲水性明显下降(接触角由65.8°上升至93.9°),而分散率由25.17%先降至11.97%,再升至71.71%。将1%的改性纳米纤维素添加到聚乳酸(PLA)中制得复合膜,机械性能测试结果表明:随着脂肪链的增长,复合膜的机械性能明显提高,其中PLA/OCATONC复合膜的拉伸强度和断裂伸长率分别达到40.2 MPa和6.39%。

Poly (Lactic Acid) Composite Strengthened with Long-chain Amidated Nanocellulose

Nano-cellulose(NCC)was used as raw material to prepare oxidized nanocellulose(TONC)by TEMPO reagent,and then TONC reacted with fatty amines that had different chain lengths under the action of catalyst to obtain fatty amine modified nanocellulose,which were prepared from octadecylamine(OCA)and named as DOATONC,TEATONC,HEATONC and OCATONC prepared from dodecylamine(DOA),tetradecylamine(TEA),hexadecylamine(HEA),respectively.Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD)and elemental analysis showed that the aliphatic chain was successfully grafted,and the crystal form.of the modified nanocellulose did not change,which was the original type Ⅰ crystal form.The angular and dispersibility tests showed that the hydrophilicity of the surface of the modified nanocellulose decreased significantly with the increase of the aliphatic chain length associated with the increment of contact angle from 65.8°to 93.9°.The dispersion decreased first and then increased,which was reflected by that the dispersion rate was 25.17% first fell to 11.97% and then rose to 71.71%.The composite membrane was prepared by adding 1% modified nanocellulose to polylactic acid(PLA).The mechanical properties test results showed that the mechanical properties of the composite membrane were significantly improved with the increase of fat chain,among which tensile strength and elongation at break of PLA/OCATONC composite membrane reached 40.2 MPa and 6.39%,respectively.