Polymer concrete: A potential construction material for desalination plants. Part I

Wood–polymer composites (WPC) of rubberwood (Hevea brasiliensis), were prepared by impregnating the wood with methyl methacrylate (MMA), and the combinations of MMA and diallyl phthalate (MMA/DAP). Polymerization was carried out by catalyst heat treatment. Impregnated samples showed significant improvements in compressive and impact strengths, hardness, and dimensional stability (toward water) over that the untreated rubberwood. © 1995 John Wiley & Sons, Inc.

Bulk polymerization of certain allyl and acrylic monomers

The engineering properties of polyurethane–poly(methyl methacrylate) simultaneous interpenetrating networks (SIN's) were evaluated. The hardness behavior reflected the observed phase inversion in the electron‐microscopic studies. The maximum ultimate tensile strength was observed at 85% polyurethane–15% poly(methyl methacrylate) IPN and was due to the filler‐reinforcing effect of the rigid poly(methyl methacrylate) phase. The ultimate tensile strenght of the 75/25 polyurethane–poly(methyl methacrylate) IPN was higher than that of the corresponding pseudo‐IPN's (only one network crosslinked) and the linear blend. The leathery and glassy compositions did not show any reinforcement in the ultimate tensile strength. This indicated that the reinforcement in the ultimate tensile strength was not directly related to interpenetration (by increased physical entanglement crosslinks), but indirectly related by reducing the rigid phase domain sizes and increasing the adhesion between the two phases, thus enhancing the filler‐reinforcing effect similar to that observed in a carbon black‐filled rubber. The tear strengths of the polyurethane‐rich IPN's pseudo‐IPN's, and linear blends were found to be higher than that of the pure polyurethane as a combined result of increased modulus and tensile strength. The weight retentions in the thermal decomposition of the IPN's, pseudo‐IPN's, and linear blends were higher than the proportional average of the component networks. The results seemed to indicate that this enhancement was related to the presence of the unzipped methyl methacrylate monomer. It was suggested that the monomers acted as radical scavengers in the polyurethane degradation, thus delaying the further reaction of the polyurethane radicals into volatile amines, isocyanates, alcohols, olefins, and carbon dioxide.

Strain-hardening fiber reinforced polymer concrete with a low carbon footprint

A thermally-accelerated aging study of 10 selected organic materials used in a fireset has been conducted. The study included both quantitative and qualitative gas analyses as well as the measurement of physical properties before and after accelerated aging. The test plan involved single material aging, as well as pairs and larger groups to look for synergistic interactions. The material types tested were epoxies, polyurethanes, polysulfides, silicones, phenolics, polyolefins, and diallyl phthalates. Only two of the materials tested showed evidence of degradation as a result of aging.

We present here a method for superposing creep measurements on polymer concrete (PC), taken at different temperatures, imposed stresses, and resin contents, onto master curves, which describe the respective responses of various PC systems and their resin binders, to compressive, tensile, and flexural loads. This treatment is extended to systems reinforced with chopped glass fiber and montmorillonite (MMT). The general applicability of this superposition is tested with creep measurements by other investigators under tensile, compressive, and flexural loads. The results make it possible to predict the long‐term creep behavior of unfilled as well as reinforced glassy polymer systems at different temperatures and load conditions from limited, short‐term data. Success of the multiple superposition suggests a generalized constitutive equation, which describes the creep compliance of these systems as a product of separable functions of each parameter in the form of shift factors for temperature (αT), stress (ασ), resin content (αυ), fiber reinforcement (αF), and MMT reinforcement (αM): J(PC) = JrαTασαυαFαMtm, where Jr is an appropriately chosen reference creep compliance. The time exponent m does not depend on the chemical nature of the polymer matrix.

The objective of this study is to analyze the applicability of current models used for estimating the mechanical properties of conventional concrete to self-consolidating concrete (SCC). The mechanical properties evaluated are modulus of elasticity, tensile strength, and modulus of rupture. As part of the study, it was necessary to build an extensive database that included the proportions and mechanical properties of 627 mixtures from 138 different references. The same models that are currently used for calculating the mechanical properties of conventional concrete were applied to SCC to evaluate their applicability to this type of concrete. The models considered are the ACI 318, ACI 363R, and EC2. These are the most commonly used models worldwide. In the first part of the study, the overall behavior and adaptability of the different models to SCC is evaluated. The specific characterization parameters for each concrete mixture are used to calculate the various mechanical properties applying the different estimation models. The second part of the analysis consists of comparing the experimental results of all the mixtures included in the database with the estimated results to evaluate the applicability of these models to SCC. Various statistical procedures, such as regression analysis and residual analysis, are used to compare the predicted and measured properties. It terms of general applicability, the evaluated models are suitable for estimating the modulus of elasticity, tensile strength, and modulus of rupture of SCC. These models have a rather low sensitivity, however, and adjust well only to mean values. This is because the models use the compressive strength as the main variable to characterize the concrete and do not consider other variables that affect these properties.

Experimental assessment of the efficiency of deep learning method in predicting the mechanical properties of polymer concretes and composites

Microstructure and rheological properties of pH-responsive core–shell particles

Allyl compounds comprise a large group of ethylenic compounds having unique reactivities and uses often contrasting with those of typical vinyl‐type compounds. Unlike monovinyl compounds, monoallyl compounds do not form homopolymers of high molecular weight by free‐radical or conventional ionic mechanisms. In contrast, many allyl compounds containing two or more reactive double bonds yield solid, high molecular weight polymers by initiation with suitable free‐radical catalysts. A number of polyfunctional allyl esters have achieved importance in polymerization and copolymerization, especially to obtain heat‐resistant cast sheets and thermoset moldings. Diallyl diglycol carbonate or diethylene glycol bis(allyl carbonate) (DADC) was developed to produce by bulk polymerization cast sheets, lenses, and other shapes of outstanding scratch resistance and optical and mechanical properties. Reaction of allyl alcohol in the presence of alkali with diethylene glycol bis(chloroformate) gives the DADC monomer, a colorless liquid of mild odor. The latter is low in toxicity, but can produce skin irritation. DADC is soluble in common organic solvents and in methyl methacrylate, styrene, and vinyl acetate. It is partially soluble in amyl alcohol, gasoline, and ligroin. It is insoluble in ethylene glycol, glycerol, and water. Usage of DADC polymers in impact‐resistant, lightweight eyewear lenses has grown rapidly and is now the principal application. The three isomeric diallyl phthalates are colorless liquids of mild odor, low volatility, and relatively slow polymerization in the early stages. At ca 25% conversion, the viscous liquid undergoes gelation and polymerization accelerates. Diallyl isophthalate (DAIP) polymerizes faster than DAP. Besides application as heat‐resistant molding powders for electronic and other applications, DAIP copolymers have been proposed for optical applications. The largest use of diallyl phthalate thermoset polymers is in moldings and coatings for electronic devices requiring high reliability under long‐term adverse environmental conditions. Monomers such as allyl methacrylate (AMA) and diallyl maleate (DAM) have applications as cross‐linking and branching agents selected especially for the different reactivities of their double bonds. DAM and DAF have pungent odors and are skin irritants. Allyl methacrylate (AMA) is used as cross‐linking agent with methacrylate esters in contact lenses. Triallyl cyanurate (TAC), 2,4,6‐tris(allyloxy)‐s‐triazine, and its isomer triallyl isocyanurate (TAIC) are used as cross‐linking agents with comonomers and for aftercuring preformed polymers such as olefin copolymers in electrical insulations.N,N‐Diallyldimethyl(DADM)ammonium salts are used for the preparation of polyelectrolytes. Copolymers of diallyldimethylammonium chloride with acrylamide have been used in electroconductive coatings.

In many bending elements, the defining calculation for ensuring the normal operation of the structure is the calculation of deflections, it is this characteristic of the structure, in particular the beams, that determines the section dimensions of the element, to ensure the necessary rigidity of structures. In view of this, the use of many polymer concrete as a material for the manufacture of bending structures becomes impossible due to the high deformation-as a consequence of the low elastic modulus. Our proposed polymer concrete based on liquid rubber (rubcon) has high compressive and tensile strengths, while the elastic modulus corresponds to ordinary cement concrete class B25. The introduction of fiber filaments into the material structure slightly increases these characteristics, and the rubber concrete obtained in this way with fiber reinforcement is called fiber rubcon. In order to ensure the possibility of calculating by way of determining the deflections of rubcon structures with cracks, we apply the principle of strain averaging of V.I. Murashov, while the uneven distribution of strains in the rubcon was taken into account by the coefficient ψk, the polymer concrete work between cracks is taken into account by the coefficient ψs, which are determined similarly to V.I. Murashov, A.S. Zalesov methods.

Polymeric mortars or concrete are special building materials which can be used to repair or strengthen localized areas of structural elements. Following research on the behaviour of retrofitting reinforced concrete circular columns with FRP composite materials and bearing in mind the high strength of polymer concretes, it was decided to develop a solution to seismic retrofit of reinforced concrete columns with polymer concrete. The mechanical characteristics of different polymer concretes and especially their performance when subjected to cyclic axial compression, several bending tests, and monotonic and cyclic axial compression tests were studied, namely the compressive strength, the tensile strength on bending and the Young's modulus. Columns were also tested under axial compression and cyclic horizontal loads. The results of these tests are shown and interpreted. It is concluded that the improved behaviour in monotonic compression of polymer concrete is essentially associated with better strength characteristics of resin, whereas its superior behaviour under cyclic loading is linked to a smoother aggregate grading curve.

The structural behavior of steel‐reinforced polymer concrete (PC) beams using unsaturated polyester resin binders based on recycled polyethylene terephthalate (PET) plastic waste is evaluated. Steel fibers are also used in some of the beams. The investigation includes load‐deflection and moment‐curvature responses, modes of failure, cracking patterns, variation of neutral axis depth with loads, strength properties, ductility index, the effect of tensile reinforcement ratio on the flexural strength of PC beams, and the effects of shear span‐to‐depth ratio, tensile reinforcement, and compressive strength on the shear strength of PC beams. The ultimate flexural strength of reinforced PC using resins based on recycled PET is compared to other reinforced concrete systems. The effects of steel fibers on the load‐deflection response and shear strength of reinforced PC beams are also evaluated. Resins using recycled PET offer the possibility of producing very good quality PC at a lower cost for structural applica...

In this work, the mechanical strength and weld line morphology of injection molded polystyrene/poly(methyl methacrylate) (PS/PMMA) blends were investigated by scanning electron microscopy (SEM) and mechanical property test. The experimental results show that the tensile strength of PS/PMMA blends get greatly decreased due to the presence of the weld line. Although the tensile strength without the weld line of PS/PMMA (70/30) is much higher than that of the PS/PMMA (30/70) blend, their tensile strength with weld line shows reversed change. The viscosity ratio of dispersed phase over matrix is a very important parameter for control of weld‐line morphology of the immiscible polymer blend. In PS/PMMA (70/30) blend, the PMMA dispersed domains at the core of the weld line are spherically shaped, which is the same as bulk. While in the PS/PMMA (30/70) blend, the viscosity of the dispersed PS phase is lower than that of the PMMA matrix, the PS phase is absent at the weld line, and PS particles are highly oriented parallel to the weld line, which is a stress concentrator. This is why weld line strength of PS/PMMA (30/70) is lower than that of PS/PMMA (70/30) blend. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1856–1865, 2002; DOI 10.1002/app.10450

The growing demand for sustainable construction materials has led to the exploration of alternative solutions to reduce environmental impact and conserve natural resources. This study investigates the feasibility of using sawdust ash (SDA) as a partial replacement for fine aggregate (sand) in concrete, focusing on its effects on compressive strength, tensile strength, and workability. Sawdust ash, a waste byproduct from wood processing industries, was incorporated into concrete mixes at varying replacement levels (0%, 5%, 10%, and 15% by weight of sand). The experimental program involved casting and testing concrete specimens at different curing periods (7, 14, 21, and 28 days) to evaluate mechanical performance. Results indicate that the inclusion of sawdust ash influences concrete properties in distinct ways. Compressive strength exhibited a gradual decline with increasing SDA content, with reductions of 2%, 7.36%, and 12% observed at 5%, 10%, and 15% replacement levels, respectively, after 28 days of curing. Conversely, tensile strength showed significant improvement, with increases of 13.04%, 22.36%, and 26.96% for the same replacement levels at 28 days. Workability, assessed via slump tests, decreased as SDA content increased, highlighting the need for mix adjustments in practical applications. The study concludes that while higher SDA content reduces compressive strength, it enhances tensile properties, making it suitable for applications requiring improved crack resistance. The optimal replacement level was identified as 5– 10% for balancing strength and sustainability. These findings contribute to the development of eco-friendly concrete by repurposing industrial waste, aligning with global sustainability goals. Further research is recommended to address long-term durability and large-scale implementation challenges.