High-performance polyurethane nanocomposites based on UPy-modified cellulose nanocrystals
作者：Tian, D. L.; Wang, F. F.*; Yang, Z. J.; Niu, X. L.; Wu, Q.; Sun, P. C.*
關鍵字：Polyurethane; Cellulose nanocrystals; Polymer nanocomposites; Bio-inspiration; High-performance.
論文來源：期刊
具體來源：Carbohydrate Polymers 2019, in press
發表時間：2019年
Densely H-bonding
assemblies are the key strategy found by nature to enhance the rupture strength
of natural polymers without sacrificing their toughness, such as spider silk,
while it still remains a great challenge using such intriguing strategy to
prepare high-performance synthesized polymer or biopolymer enhanced polymer
nanocomposites. To address this challenge, we report here a bio-inspired
strategy using densely H-bonding assembly for facile fabrication of high
performance polyurethane (PU) nanocomposites reinforced by hydroxyl-rich cellulose
nanocrystals (CNCs) functionalized with 2-ureido-4-[1H]-pyrimidinone motifs
(CNC-UPy) containing self-complementary hydrogen bonds. These PU/CNC-UPy
nanocomposites showed remarkably improved mechanical strength without
sacrificing the elongation at break and toughness compared to pure PU matrix. Differential
scanning calorimetry(DSC) results indicates that CNC-UPy could induce the
formation of long range ordering of hard segment domains, due to the
strong hydrogen bonding interactions between UPy motifs attached on CNC-UPy and
PU matrix. Furthermore, wide angle X-ray diffraction (WAXD) measurements
demonstrated that the strain-induced crystallization (SIC) was enhanced
significantly by introducing CNC-UPy into PU, leading to a large stress at
break. The enhanced interfacial H-bonding interactions between CNC and PU though
UPy anchoring could overcome the inherent trade-off between the stiffness and
toughness of polymer composites. The proposed bio-inspired strategy using densely
H-bonding assembly will be with more extensive application prospects.