ABSTRACT In this work, waste Medium Density Fiberboard (MDF) and wood were used as reinforcing fillers in sandwich composites. MDF powder was used in different proportions in rigid polyurethane (PU) foams as well as in different grain sizes; the outer boards were produced with a composite of low-density polyethylene (LDPE) and ethylene vinyl acetate copolymer (EVA) (80:20) reinforced with Pinus elliottii wood powder (20%). The foams were assessed for compressive strength, density and morphology. The composites with a sandwich structure were evaluated for flexural strength and thermal insulation. An increase in the density of the foams was observed with an increase in the content and a reduction of up to 0.05 MPa in compressive strength when MDF fillers were added. The insertion of fillers in PU foams causes the cells to collapse, leading to greater contraction of the foam during the expansion process. In the analyses carried out on the composite with a sandwich structure, a variation in flexural strength was observed, with higher strengths at pure PU foam compared to the composites with the PU10A and PU10B core, and lower strength values in the other loaded samples. work (MDF (PU sizes lowdensity low LDPE (LDPE EVA (EVA 8020 80 20 (80:20 20%. 20% . (20%) morphology insulation 005 0 05 0.0 added collapse process PUA A PUB B core samples 802 8 2 (80:2 (20% 00 0. (80: (20 (80 (2 (8 (

RESUMO Neste trabalho foram utilizados resíduos de Medium Density Fiberboard (MDF) e madeira como cargas de reforço em compósitos de estrutura sanduiche. O MDF foi utilizado em diferentes proporções em espumas rígidas de poliuretano (PU) bem como em diferentes granulometrias; as placas externas foram produzidas com um compósito de polietileno de baixa densidade (PEBD) e copolímero de etileno acetato de vinila (EVA) (80:20) reforçadas com pó de madeira Pinus elliottii (20%). As espumas foram avaliadas quanto a resistência à compressão, densidade e morfologia. Já os compósitos com estrutura sanduíche foram avaliados quanto a resistência à flexão e isolamento térmico. Observou-se aumento na densidade das espumas com aumento do teor de cargas e redução de até 0,05 MPa na resistência à compressão quando adicionado cargas de MDF. A inserção de cargas nas espumas de PU gera colapso das células, levando a maior contração da espuma durante o processo de expansão. Nas análises realizadas no compósito com estrutura sanduíche, observou-se uma variação na resistência a flexão, com resistências superiores à espuma de PU puro para os compósitos com o núcleo de PU10A e PU10B, e valores de resistência menores nas demais amostras com carga. (MDF sanduiche (PU granulometrias PEBD (PEBD EVA (EVA 8020 80 20 (80:20 20%. 20% . (20%) morfologia térmico Observouse Observou se 005 0 05 0,0 células expansão observouse observou PUA PU10B PUB B carga 802 8 2 (80:2 (20% 00 0, (80: (20 (80 (2 (8 (

Abstract A thermosetting epoxy polymer composed of diglycidyl ether of bisphenol A and triethylenetetramine (DGEBA/TETA) was modified by incorporating flexographic photopolymer plate residues (rubber microparticles). The photopolymer plate residues were processed in two ways: (a) by grinding and performing particle size classification (where the resulting samples were denoted PP) and (b) by polyester layer separation and grinding the elastomeric fraction by cryogenic grinding (where the resulting samples were denoted ER). Both residual particles were incorporated into the epoxy at concentrations of 2.5, 5 and 7.5 wt%. The main results indicate that PP was not efficient as a modifier of the epoxy system. A reduction in mechanical properties (maximum tensile strength and deformation) was observed in the samples produced with PP in different concentrations. But, when the ER is incorporated, an increase in tensile property and in the deformation capacity, as well as impact resistance was observed in samples produced with ER. Scanning electron microscopy analysis showed a greater presence of voids in formulations produced with PP, which corroborates the decrease in the tensile strength of these samples. DGEBA/TETA DGEBATETA DGEBA TETA (DGEBA/TETA rubber microparticles. microparticles . microparticles) ways (a where b (b ER) 25 2 2.5 75 7 7. wt wt% system maximum But capacity 2.

Abstract Oil spills into water have been an environmental concern since the beginning of large-scale oil extraction. In this study, flexible open-cell polyurethane (PU) foams with added microcrystalline cellulose (MCC) were formulated and chemically modified with organosilane for use as an absorbent system for oil spill cleanup in water. The influence of cellulose concentration on mechanical properties and chemical treatment with organosilane was evaluated. The primary findings indicate that the surface treatment of the solid fraction of the foams was effective, as indicated by the contact angle, increasing the hydrophobicity of the samples. Because of the increased roughness of the PU solid fraction and the cellulose reactivity, the mechanical compressive strength and thickness of the organosilane layer increased with increasing MCC content. However, the higher the MCC content in the composition, the higher was the density, which reduced the sorption capacity of the samples. largescale large scale extraction study opencell open cell (PU (MCC evaluated effective angle samples reactivity However composition density