Weiwei Tie,Surjya Sarathi Bhattacharyya,Zhi Zheng,Kyung Jun Cho,Tae Hyung Kim,Young Jin Lim,Seung Hee Lee
To develop stable polymer films which had high orientational ordering of carbon nanotube for polarization-dependent light modulator, we present a new concept for electric-field induced alignment of mesogenic carbon nanotubes (m-CNTs) in reactive mesogen host (RMS) fixed by ultraviolet (UV) polymerization. Covalent modification of m-CNTs was performed using structure-tailored mesogenic units [4-(6-hydroxyhexanolxy)-4’-carbonitrile, PCNOH] in esterification reaction based on 100–500 nm long CNTs shortened by acid oxidation cutting, confirmed through 1H NMR, FT-IR, Raman and XPS spectroscopy. Dynamic orientation of m-CNTs in soft m-CNT/RMS composite without aggregates was observed on a large scale by polarized optical microscopy, in which m-CNTs aligns along the electric field direction. It was reasonable the mesogenic segments introduced onto m-CNTs weakened van der walls interactions between the nanotubes by increasing steric repulsion, and then effectively improved the favourable affinity of m-CNTs with RMS molecules. Direct UV-induced polymerization of RMS molecules stabilized the orientational ordering of m-CNTs confirmed by Raman spectroscopy, and the obtained film also exhibited anisotropic light absorption depending on the polarization direction of an incident light. The facile methodology described in this study to generate oriented films of m-CNTs-in-RMS broadened the scope of potential applications of modulator devices and versatile functional composites with anisotropic physical properties.
Abstract Cellulose nanocrystals (CNC)/poly(butylene adipate- co -butylene terephthalate) composites enhanced compatibility with phthalic anhydride were one-step prepared via melt blending. The obtained composites then underwent squeezing treatment in a two-roll milling equipment at a given temperature. CNC/PBAT composites were separated and then tested via FTIR and UV–Vis spectrophotometer. During reactive blending, phthalic anhydride selectively reacts with CNC. Before squeezing, tensile strength of CNC/PBAT composites is weakened with increasing phthalic anhydride content. After squeeze treatment at an extension ratio of 6, tensile strength of CNC/PBAT (3/97) is dramatically increased from 29.6 to 148.0 MPa, which is much higher than that of pristine PBAT 85.0 MPa. SEM and WAXD results show that PBAT crystallinity is increased after orientation, and CNC show an orientation arrangement along force direction in PBAT matrix.
Kang Ren,Juanqin Xue,Bin Liu,Heping Wang,Yongqiang Tian,Xue Han,Changbin Tang
Despite Ti 3 C 2 T x- based filler has gained enormous application in improving the anti-corrosion of epoxy coatings, it is still insufficient to achieve the quality standard to face long-term service conditions. In this work, a composite coating integrated with Ti 3 C 2 T x and epoxy resin was prepared, which was fabricated by functionalizing Ti 3 C 2 T x through a strong cationic poly (diallyl dimethyl ammonium) chloride (PDDA) electrostatic adsorption and ionic liquids (ILs) to improve the chemical stability, and then the functionalized Ti 3 C 2 T x was controlled to parallelly distributed in epoxy under the external electric field. Results showed that Ti 3 C 2 T x nanosheets fillers in the prepared epoxy coating exhibit a flat arrangement for resisting infiltration. After immersion in 3.5 wt% NaCl solution for 28 days, the low-frequency impedance modulus of the prepared PDDA-ILs@Ti 3 C 2 T x /EP coating was about 1–2 orders of magnitude compared to that of epoxy coating and was maintained above 10 8 Ω. cm 2 . Integrating the triple effect of the interfacial interaction, directional-aligned barrier effect and intelligent effect formed by ILs, it can provide new idea for developing MXene-based smart coating for the corrosion protection of oil and gas field pipelines steel.
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