title: Three-Dimensional Nanoporous Cellulose Gels as a Flexible Reinforcement Matrix for Polymer Nanocomposites.
abstract: With the world's focus on utilization of sustainable natural resources, the conversion of wood and plant fibers into cellulose nanowhiskers/nanofibers is essential for application of cellulose in polymer nanocomposites. Here, we present a novel fabrication method of polymer nanocomposites by in-situ polymerization of monomers in three-dimensionally nanoporous cellulose gels (NCG) prepared from aqueous alkali hydroxide/urea solution. The NCG have interconnected nanofibrillar cellulose network structure, resulting in high mechanical strength and size stability. Polymerization of the monomer gave P(MMA/BMA)/NCG, P(MMA/BA)/NCG nanocomposites with a volume fraction of NCG ranging from 15% to 78%. SEM, TEM, and XRD analyses show that the NCG are finely distributed and preserved well in the nanocomposites after polymerization. DMA analysis demonstrates a significant improvement in tensile storage modulus E' above the glass transition temperature; for instance, at 95 °C, E' is increased by over 4 orders of magnitude from 0.03 MPa of the P(MMA/BMA) up to 350 MPa of nanocomposites containing 15% v/v NCG. This reinforcement effect can be explained by the percolation model. The nanocomposites also show remarkable improvement in solvent resistance (swelling ratio of 1.3-2.2 in chloroform, acetone, and toluene), thermal stability (do not melt or decompose up to 300 °C), and low coefficients of thermal expansion (in-plane CTE of 15 ppm·K(-1)). These nanocomposites will have great promising applications in flexible display, packing, biomedical implants, and many others.
authors.affiliation: College of Chemistry & Molecular Sciences, Wuhan University , Wuhan 430072, People's Republic of China.
authors.forename: Zhuqun
authors.initials: Z
authors.lastname: Shi
authors.affiliation: College of Chemistry & Molecular Sciences, Wuhan University , Wuhan 430072, People's Republic of China.
authors.forename: Junchao
authors.initials: J
authors.lastname: Huang
authors.affiliation: College of Chemistry & Molecular Sciences, Wuhan University , Wuhan 430072, People's Republic of China.
authors.forename: Chuanjun
authors.initials: C
authors.lastname: Liu
authors.affiliation: College of Chemistry & Molecular Sciences, Wuhan University , Wuhan 430072, People's Republic of China.
authors.forename: Beibei
authors.initials: B
authors.lastname: Ding
authors.affiliation: Graduate School of Agricultural and Life Sciences, The University of Tokyo , Tokyo, Japan.
authors.forename: Shigenori
authors.initials: S
authors.lastname: Kuga
authors.affiliation: College of Chemistry & Molecular Sciences, Wuhan University , Wuhan 430072, People's Republic of China.
authors.forename: Jie
authors.initials: J
authors.lastname: Cai
authors.affiliation: College of Chemistry & Molecular Sciences, Wuhan University , Wuhan 430072, People's Republic of China.
authors.forename: Lina
authors.initials: L
authors.lastname: Zhang
mesh_terms: D002482:Cellulose / Q000737:chemistry*; D005782:Gels / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry; D018625:Microscopy, Atomic Force; D053761:Nanocomposites / Q000737:chemistry*; D058608:Nanopores; D011108:Polymers / Q000737:chemistry*; D012997:Solvents; D013314:Stress, Mechanical; D013696:Temperature; D013818:Thermogravimetry; D014867:Water / Q000737:chemistry
chemical_list: D005782:Gels; D020100:Hydrogels; D011108:Polymers; D012997:Solvents; D014867:Water; D002482:Cellulose
keywords: mechanical properties; nanoporous cellulose gels; polymer nanocomposites; solvent resistance; thermal expansion