First-principles study on the mechanical properties of citric acid-modified cellulose composite polymeric materials
Topic(s) : Material science
Co-authors :
Takeru KOMYO (JAPAN), Luo CHAO (JAPAN), Yasutomo UETSUJI (JAPAN)Abstract :
The carbon cycle is the ideal goal we must achieve towards a carbon-neutral society. The first step towards this goal is to reduce the number of petroleum-derived components. Cellulose is of plant origin and is a very rich biofiller. Cellulose is effective as one of reinforcing fillers in polymer composites when mixed with the polymer matrix. However, the content of cellulose fillers in polymer composites is generally low and further use of cellulose fillers is important to reduce the use of petroleum-based resources. However, it is difficult to increase the cellulose content of polymer composites while improving their toughness as well as Young's modulus. On the other hand, another approach to reducing the use of petroleum-based resources is to toughen polymeric materials to improve their durability. Polymeric materials can be toughened by energy dissipation mechanisms. Preparations of toughened polymeric materials based on various concepts incorporating supramolecular cross-linking, topological cross-linking, sacrificial bonding, structural uniformity and a single cross-network (SC) of secondary permeable linear polymers have been implemented.
Therefore, in this study, composite materials employing citric acid-modified cellulose (CAC) as a cellulose filler for the reinforcement, 2-Hydroxypropyl acrylate (HPA) as the primary polymer of the matrix and 2-methoxyethyl acrylate (MEA) as the secondary polymer were targeted as materials that simultaneously satisfy the two properties of sustainability and toughness. Polymer composites were created by introducing host-guest composites of β-cyclodextrin (βCD), adamantane (Ad) and permeable linear polymers to toughen the matrix. The mechanical properties were determined by load tests, and the underlying mechanisms of the mechanical properties were analyzed atomistically by first-principles calculations based on density functional theory.
First, the effect of citric acid denaturation on the interfacial bonding between the matrix polymer and CNC was clarified. Stress-strain relationships were obtained for CNC/HPA, CNC/MEA, CAC/HPA and CAC/MEA using a tensile loading test model, and the difference in the bond strength of each interface with and without citric acid denaturation was quantified with reference to the bond strength between CNC/CNC. The results showed that citric acid denaturation was effective for both HPA and MEA, with a maximum tensile stress of 239% and 206%, respectively, in the maximum tensile stress.
Secondly, stress-strain relationships were obtained for the bonding units within the CAC composites, i.e. between CAC/HPA, CAC/MEA, HPA/HPA, MEA/MEA and MEA/HPA molecules, as well as for the host-guest bond structure βCD /Ad, and the mechanical properties were compared. The results show that first-principles calculations are atomistically consistent with the experimental results for the change in mechanical properties upon mixing of HPA and MEA.
Therefore, in this study, composite materials employing citric acid-modified cellulose (CAC) as a cellulose filler for the reinforcement, 2-Hydroxypropyl acrylate (HPA) as the primary polymer of the matrix and 2-methoxyethyl acrylate (MEA) as the secondary polymer were targeted as materials that simultaneously satisfy the two properties of sustainability and toughness. Polymer composites were created by introducing host-guest composites of β-cyclodextrin (βCD), adamantane (Ad) and permeable linear polymers to toughen the matrix. The mechanical properties were determined by load tests, and the underlying mechanisms of the mechanical properties were analyzed atomistically by first-principles calculations based on density functional theory.
First, the effect of citric acid denaturation on the interfacial bonding between the matrix polymer and CNC was clarified. Stress-strain relationships were obtained for CNC/HPA, CNC/MEA, CAC/HPA and CAC/MEA using a tensile loading test model, and the difference in the bond strength of each interface with and without citric acid denaturation was quantified with reference to the bond strength between CNC/CNC. The results showed that citric acid denaturation was effective for both HPA and MEA, with a maximum tensile stress of 239% and 206%, respectively, in the maximum tensile stress.
Secondly, stress-strain relationships were obtained for the bonding units within the CAC composites, i.e. between CAC/HPA, CAC/MEA, HPA/HPA, MEA/MEA and MEA/HPA molecules, as well as for the host-guest bond structure βCD /Ad, and the mechanical properties were compared. The results show that first-principles calculations are atomistically consistent with the experimental results for the change in mechanical properties upon mixing of HPA and MEA.