Impact of the Surface Properties of Cellulose Nanocrystals on the Crystallization Kinetics of Poly(Butylene Succinate)

Abstract

The hydrophilicity of cellulose nanocrystals (CNCs) is a major challenge for their processing with hydrophobic polymers and matrices. As a result, many surface modifications have been proposed to hydrophobize CNCs. The authors showed in an earlier study that grafting alcohols of different chain lengths onto the surface of CNCs using toluene diisocyanate (TDI) as a linker can systematically hydrophobize CNCs to a water contact angle of up to 120° depending on the alcohol chain length. Then, the hydrophobized CNCs were used to mechanically reinforce poly(butylene succinate) (PBS), which is a hydrophobic polymer. As a result of hydrophobization, PBS/CNCs interfacial adhesion and the composite mechanical properties significantly improved with the increasing CNC contact angle. Continuing on these results, this paper investigates the impact of CNC surface properties on the crystallization behavior of PBS using differential scanning calorimetry (DSC). The results showed that the crystallization temperature of PBS increased from 74.7 °C to up to 86.6 °C as a result of CNC nucleation activity, and its value was proportionally dependent on the contact angle of the CNCs. In agreement, the nucleation activity factor (φ) estimated using Dobreva and Gutzow’s method decreased with the increasing CNC contact angle. Despite the nucleation action of CNCs, the rate constant of PBS crystallization as estimated using the Avrami model decreased in general as a result of a prevailing impeding effect. This decrease was minimized with increasing the contact angle of the CNCs. The impeding effect also increased the average activation energy of crystallization, which was estimated using the Kissinger method. Moreover, the Avrami exponent (n) decreased because of CNC addition, implying a heterogeneous crystallization, which was also apparent in the crystallization thermograms. Overall, the CNC addition facilitated PBS nucleation but retarded its crystallization, and both processes were significantly affected by the surface properties of the CNCs.

Effect of TDI-Assisted Hydrophobic Surface Modification of Microcrystalline Cellulose on the Tensile Fracture of MCC/PLA Composite, and Estimation of the Degree of Substitution by Linear Regression

“…The least WCA (119.25°) was recorded at 1 h, and the maximum recorded WCA (145.74°) was recorded at 24 h. The result of the WCA was compared to earlier reports of 90°, 12 96.9°, 33 84°, 30 106°, 34 90.1°, 31 104°, and 120°. 35 The carbamation reaction improved the wetting ability of MCC from hydrophilic to a highly hydrophobic state. This high hydrophobic property can expand MCC's use in different applications, especially in its interaction with nonpolar matrixes for composite fabrication.…”

Bamboo Fiber Based Cellulose Nanocrystals/Poly(Lactic Acid)/Poly(Butylene Succinate) Nanocomposites: Morphological, Mechanical and Thermal Properties

“…Further, Pirani [ 20 ] investigated the mechanical properties of electro spun PLA-CNC composite developed using aqueous mixing and freeze-drying techniques. CNCs have also been reinforced in PBS by various researchers [ 21 , 22 ]. Thus, it is interesting to determine the influence of PBS and CNC together, on the properties of the PLA.…”

Effect of Silver Nanoparticles on the Melting Behavior, Isothermal Crystallization Kinetics and Morphology of Polyoxymethylene

“…On one hand, the physical properties of POM are governed by the crystallization [10]. On the other hand, the crystallization behavior of POM depends on its supramolecular structure [11,12]. However, POM has a linear molecular chains as (-CH 2 -O-) n structure which leads to high crystallinity, which limits its application [13][14][15].…”