Banca de QUALIFICAÇÃO: THIAGO SILVA RAMOS

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE: THIAGO SILVA RAMOS
DATA: 31/07/2026
HORA: 09:00
LOCAL: on line
TÍTULO:

Reengineering Paper Tube Waste into Lignin-Containing Cellulose Micro/Nanofibrils for Reinforced Paper-Based Composites

PALAVRAS-CHAVES:

Lignocellulosic wastes; Circular economy; Surface modification; Rheological behavior; Adhesive reinforcement; Stiffness enhancement

PÁGINAS: 90
GRANDE ÁREA: Ciências Agrárias
ÁREA: Recursos Florestais e Engenharia Florestal
SUBÁREA: Tecnologia e Utilização de Produtos Florestais
ESPECIALIDADE: Tecnologia de Celulose e Papel
RESUMO:

The valorization of lignocellulosic wastes for the production of micro/nanomaterials represents a promising strategy for developing sustainable biomaterials aligned with circular economy principles. Lignin-containing cellulose micro/nanofibrils (LCMNF) were produced from industrial paper tube waste through alkaline pretreatment followed by mechanical fibrillation, resulting in a micro/nanofibrillar network with high reinforcing potential. Surface modification of LCMNF with polyethylene glycol 400 demonstrated that intermediate concentrations of 6 wt% promoted improved fibril dispersion and the formation of a cohesive network, increasing the initial viscosity from 3.63 to 7.26 Pa·s and enhancing structural stability under shear. Subsequently, the modified LCMNF were incorporated into sodium silicate adhesive at concentrations ranging from 0.5 to 2.0 wt%, increasing viscosity and rheological stability while maintaining the shear-thinning behavior of the modified sodium silicate adhesives. Single-lap shear tests revealed a 41% increase in shear modulus for the formulation containing 1 wt% LCMNF, indicating improved stiffness of the adhesive bond. FTIR, optical microscopy, scanning electron microscopy, and Energy Dispersive X-Ray Spectroscopy analyses confirmed the formation of a stabilized micro/nanofibrillar network through hydrogen bonding, as well as more continuous and homogeneous adhesive bond lines. The developed adhesives were subsequently applied to paper-based composites, resulting in 38% and 13% increases in the modulus of rupture and modulus of elasticity, respectively, for laminated structures, whereas industrial cylindrical structures subjected to diametral compression exhibited no statistically significant improvements. Qualitative finite element analysis demonstrated that these contrasting responses were determined by stress distribution associated with structural configuration, highlighting that reinforcement efficiency depends not only on adhesive properties but also on structural geometry and loading conditions. Overall, these results validate the utilization of paper tube waste as a source of micro/nanostructured reinforcement. The engineered sodium silicate adhesives and laminated composites present a technologically viable strategy, bridging the gap between industrial waste recycling and advanced materials manufacturing.

MEMBROS DA BANCA:
Externo à Instituição - RAPHAEL PALUCCI ROSA (UNIVERSITY OF BERGAMO) - AICS (Membro)
Externo à Instituição - MATHEUS CORDAZZO DIAS - UFRA (Membro)
Externo à Instituição - LINA BUFALINO - UFRA (Membro)
Presidente - GUSTAVO HENRIQUE DENZIN TONOLI (Membro)
Interno - FELIPE GOMES BATISTA - UFLA (Suplente)
Externo à Instituição - ANAND RAMESH SANADI - KU (Membro)
Externo à Instituição - ADRIANO REIS PRAZERES MASCARENHAS - UNIR (Suplente)