Surface-Initiated Initiators for Continuous Activator Regeneration (SI ICAR) ATRP of MMA from 2,2,6,6–tetramethylpiperidine–1–oxy (TEMPO) Oxidized Cellulose Nanofibers for the Preparations of PMMA Nanocomposites
oleh: Cheng-Wei Tu, Fang-Chang Tsai, Chi-Jung Chang, Cheng-Han Yang, Shiao-Wei Kuo, Jiawei Zhang, Tao Chen, Chih-Feng Huang
| Format: | Article |
|---|---|
| Diterbitkan: | MDPI AG 2019-10-01 |
Deskripsi
An effective method of oxidation from paper pulps via 2,2,6,6−tetramethylpiperidine−1−oxy (TEMPO) compound to obtain TEMPO-oxidized cellulose nanofibers (TOCNs) was demonstrated. Following by acylation, TOCN having an atom transfer radical polymerization (ATRP) initiating site of bromoisobutyryl moiety (i.e., TOCN−Br) was successfully obtained. Through a facile and practical technique of surface-initiated initiators for continuous activator regeneration atom transfer radical polymerization (SI ICAR ATRP) of methyl methacrylate (MMA) from TOCN−Br, controllable grafting polymer chain lengths (<i>M</i><sub>n</sub> = ca. 10k−30k g/mol) with low polydispersity (PDI < 1.2) can be achieved to afford TOCN−<i>g</i>−Poly(methyl methacrylate) (PMMA) nanomaterials. These modifications were monitored by Fourier-transform infrared spectroscopy (FT−IR), scanning electron microscopy (SEM), electron spectroscopy for chemical analysis (ESCA), and water contact angle analysis. Eventually, TOCN−<i>g</i>−PMMA/PMMA composites were prepared using the solvent blending method. Compared to the pristine PMMA (<i>T</i><sub>g</sub> = 100 °C; tensile strength (<i>σ</i><sub>T</sub>) = 17.1 MPa), the composites possessed high transparency with enhanced thermal properties and high tensile strength (<i>T</i><sub>g</sub> = 110 °C and <i>σ</i><sub>T</sub> = 37.2 MPa in 1 wt% TOCN containing case) that were investigated by ultraviolet-visible spectroscopy (UV-Vis), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), and tensile tests. We demonstrated that minor amounts of TOCN−<i>g</i>−PMMA nanofillers can provide high efficacy in improving the mechanical and thermal properties of PMMA matrix.