The dry-pulp direct-kneading method is an industrially viable, low-energy process to manufacture cellulose nanofiber (CNF) reinforced polymer composites, where chemically modified pulps can be nanofibrillated and dispersed uniformly in the polymer matrix during melt-compounding. In this study, cellulose fibers with different sizes, ranging from surface-fibrillated pulps with 20 µm in width to fine CNFs with 20 nm in width were prepared from softwood bleached kraft pulps (NBKPs) using a refiner and high-pressure homogenizer (HPH). These cellulose fibers were modified with alkenyl succinic anhydride (ASA), and then dried. The dried ASA-treated cellulose fibers were used as a feed material for melt-compounding in the dry-pulp direct kneading method to fabricate CNF reinforced high-density polyethylene (HDPE). When surface-fibrillated pulps were employed as a feed material, the pulps were nanofibrillated and dispersed uniformly in the HDPE matrix during the melt-compounding, and the composites had much better properties (i.e., much higher tensile modulus and strength and much lower coefficient of thermal expansion) than the composites produced using the pulps without pre-fibrillation. However, when CNFs were used as a feed material, the CNFs were shortened and agglomerated during the melt-compounding, thus deteriorating the properties of the composites. The study concludes that the pre-fibrillation of pulps had a significant impact on the morphology and properties of the composites. Unexpectedly, the surface-fibrillated pulp, which can be produced cost-effectively using a refiner at an industry scale, was a more suitable form than the CNF as a feed material for melt-compounding in the dry-pulp direct kneading method.

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Posted 03 Jun, 2021
On 12 Jul, 2021
Received 29 May, 2021
Invitations sent on 29 May, 2021
On 28 May, 2021
On 28 May, 2021
On 27 May, 2021
Posted 03 Jun, 2021
On 12 Jul, 2021
Received 29 May, 2021
Invitations sent on 29 May, 2021
On 28 May, 2021
On 28 May, 2021
On 27 May, 2021
The dry-pulp direct-kneading method is an industrially viable, low-energy process to manufacture cellulose nanofiber (CNF) reinforced polymer composites, where chemically modified pulps can be nanofibrillated and dispersed uniformly in the polymer matrix during melt-compounding. In this study, cellulose fibers with different sizes, ranging from surface-fibrillated pulps with 20 µm in width to fine CNFs with 20 nm in width were prepared from softwood bleached kraft pulps (NBKPs) using a refiner and high-pressure homogenizer (HPH). These cellulose fibers were modified with alkenyl succinic anhydride (ASA), and then dried. The dried ASA-treated cellulose fibers were used as a feed material for melt-compounding in the dry-pulp direct kneading method to fabricate CNF reinforced high-density polyethylene (HDPE). When surface-fibrillated pulps were employed as a feed material, the pulps were nanofibrillated and dispersed uniformly in the HDPE matrix during the melt-compounding, and the composites had much better properties (i.e., much higher tensile modulus and strength and much lower coefficient of thermal expansion) than the composites produced using the pulps without pre-fibrillation. However, when CNFs were used as a feed material, the CNFs were shortened and agglomerated during the melt-compounding, thus deteriorating the properties of the composites. The study concludes that the pre-fibrillation of pulps had a significant impact on the morphology and properties of the composites. Unexpectedly, the surface-fibrillated pulp, which can be produced cost-effectively using a refiner at an industry scale, was a more suitable form than the CNF as a feed material for melt-compounding in the dry-pulp direct kneading method.

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