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Composite films were studied as possible candidates for the central or support layer of synthetic paper in a multilayer structure. Recycled post-consumer polypropylene films were reinforced with inorganic fillers at various compositions and under several processing conditions, with the aim of optimizing the physical and mechanical properties of rigidity and low density. Three types of CaCO3, with and without surface treatment of the particles, were used, but only the treated ones were suitable for use in paper films. These samples were then used to analyze possible correlations of properties with composition and processing conditions, varying the CaCO3 particle size distribution and the film processing method, from casting extrusion (flat die) to blown-film extrusion (tubular die). An increase in film stiffness was observed as a function of CaCO3 content and a concentration of 30% CaCO3 was found to be best for the specific application. The flat films were stiffer than the tubular ones. The densities of all the composite films were considered high, compared to a pulp-based paper and a commercial synthetic paper. No significant effect on the physical-mechanical properties analyzed was observed when the CaCO3 particle size distribution was varied. Microcavities were found to form at the surface of flat films submitted to a bi-orientation process performed at laboratory scale; no other sample showed this surface morphology.

Copyright of Ciência Florestal (01039954) is the property of Ciencia Florestal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Mortar coatings have a major influence on a building’s aesthetics, valorization, and habitability, with significant effects on the mechanical behavior of masonry walls. Multiple types of meshes can be embedded in plaster to enhance both masonry and coating’s mechanical behavior, restrain crack formation, enhance the bonding between layers, and increase the wall’s seismic resistance. The reinforcement technique has simple execution and is suitable for many applications, including the strengthening of non-load bearing walls, façade performance improvement, and restoration of historical buildings. However, there is an absence of guidelines and specifications for design and execution, resulting in high variability in field applications due to the many variables involved and few in-depth studies. This paper presents a systematic review of the effects of mesh reinforcement in cementitious mortar coatings and its major applications. Mortar and mesh parameters and influences, the status of analytical and simulation models, and suggestions for future research are described.

This paper aims to conduct a comparative analysis of composite materials subjected to apparently density tests and thermal tests. It will be made three samples. These materials will have as polymer matrix polyurethane (PU) with base of castor beans. A sample will be done with pure PU and the other two will be reinforced with sawdust and other wood-shaving in the proportion of 20% of the body made of pure PU. The PU was obtained commercially, while the wood was recycled from the tailings joinery. Through the thermal tests, it became possible to evaluate the behavior of its thermal properties. The fabrications of composites were made in metallic molds. With the study, we concluded that the materials reinforced with wood have a lower thermal conductivity and they are more apt to use as thermal insulation. [ABSTRACT FROM AUTHOR]

Thermal insulation is used in the protection of heated or cooled surfaces by the low thermal conductivity materials, where the rigid polyurethane foams (PUR) are the most widely applied. Glass wastes are not usable by the recycling industry, so some researches looking for a harnessing of this glassy residue to apply it as reinforcement materials. In this paper were developed PUR composites filled with refined glass powder (GP) to compare with pure PUR and to evaluate their suitability as thermal insulators. PV was milled and sifted to obtain two different particle sizes. These particles were characterized by laser granulometry, XRD and XRF analyses. The PUR+PV samples were produced by application of PV of 5, 10 and 20 percentage mass. The characteristics of samples were analyzed by the thermal conductivity, density and compressive strength tests. The results showed the properties of PUR composites are influenced by the addition of PV on PUR matrix. Thus, it was found that the compression strength (except to PV20-100) and the density of the PUR + PV composites were higher than that of pure PUR. The thermal conductivity of the PUR + PV composites showed a range of 0.035 until 0.045 W/m-K. This can suggest that the inclusion of PV didn't affect significantly the thermophysical properties when they were compared to pure PUR (0.040 W/m-K). Therefore, the applicability of the glass waste contributed to improve the PUR strength, and also its thermal insulation was not reduced. This can allow high economy and environmental preservation. [ABSTRACT FROM AUTHOR]

ABSTRACT The glued laminated timber (glulam) is a composite material obtained from the bonding of wood laminae arranged with parallel fibers put together. The purpose of this paper was to evaluate the influence of the number of laminae on the mechanical behavior of glulam of Toona ciliata produced with vegetable-based polyurethane adhesive. The glulam beams were produced with lamellae in the dimensions of 6.0 x 1.5 x 120.0 cm, with 3 beams being made per treatment, which were structurally composed by 5, 7 and 9 laminae. The polyurethane adhesive based on castor oil was used, applying a grammage of 350 g m-². For the technological characterization of the wood the moisture in the dry base, bulk density, chemical characterization, compressive strength parallel to the fibers, shear and modulus of elasticity (MOE) and rupture (MOR) in the static bending test. While the properties of modulus of elasticity (MOE), modulus of rupture (MOR), shear strength, delamination and visualization of the glue line through photomicrographs of the laminated wood samples were determined for glulam beams. The results showed that the beams with 5 laminae presented values similar to solid wood. The increase in the number of laminae provided lower values for stiffness and strength of the beams. The photomicrographs showed the quality of the bonding and the satisfactory values for shear strength and delamination, indicating the viability of the species under study for situations with high moisture content.

This paper examined the potential of manufacturing bonded particleboards using timber industry waste of Pinus spp. Panels were evaluated with 0.6 and 0.8 g cm-3 of density and produced with urea-formaldehyde resin and bi-component polyurethane resin based on castor oil. Panels were made of particles with nominal dimensions 40 x40 cm and a thickness of1 cm. As process parameters was adopted 2 - 5% moisture content, temperature ranging from 90 to130°C, average pressure of 5.0 MPa and resin content from 10 to 15% of the weight particles. This study determined physical-mechanical properties of the panels, following the recommendations of ABNT (2006) NBR 14810. The results indicated statistically significant difference (p < 0.05) in physical and mechanical properties of the panels studied. Panels were classified by ANSI (1993) A208.1 – Mat-formed wood particleboard: Specification, as of low and medium density. Scanning electron microscopy images (SEM) illustrated the agglomeration of particles for the different resins. The polyurethane resin based on castor oil stood out as a viable alternative in the production of particleboards with timber waste.

This paper describes the preparation of magnetic copolymer obtained from suspension polymerization of styrene (Sty) and divinylbenzene (DVB) in the presence of iron particles treated and not treated with oleic acid. The magnetic copolymers were characterized according to their morphology, particle size distribution and magnetic properties. The results show that incorporation of iron particles significantly changed the particles’ morphology. All samples presented higher saturation magnetization than the values reported in the literature and the particle size distribution was more monodisperse when the polymerization was conducted with 5%wt of benzoyl peroxide (BPO).