Development Of New Resins Research Articles

Experimental analysis of the SHBT approach for the dynamic modeling of a composite hollow shaft

Composite materials have been extensively used in engineering applications over the past few decades, enabling new possibilities for engineering design. The limitations faced by composites have been eliminated through the development of new resins, fibers, and configurations. Thus, composite shafts appear to be an interesting solution for many rotating machinery applications due to their associated low weight, high-strength, high-temperature resistance, mechanical properties manipulation, and thermal cycling resistance as compared with metallic shafts. For the modeling of composite shafts, simplified theories are often used. In the present contribution, a finite element model (FE model) based on the Simplified Homogenized Beam Theory (SHBT) was used to predict the dynamic behavior of a thick-walled composite hollow shaft. The FE model of the shaft is based on the Timoshenko beam theory. A test rig presenting a thick-walled carbon-epoxy composite hollow shaft, two aluminum discs, and two self-aligning ball bearings was used to validate the mentioned FE model. In this case, numerical and experimental frequency response functions (FRFs) and unbalance responses were compared. Results show promising outcomes from the considered FE model regarding the prediction of the first critical speed and the corresponding unbalance responses of the composite rotor.

Kinetics studies and characterization of poly(furfuryl alcohol) for use as bio‐based furan novolacs

ABSTRACTPoly(furfuryl alcohol) (PFA) is an attractive target for the development of bio‐based novolac resins. However, control of the polycondensation reaction is not well understood and side reactions are an important factor for PFA and the development of new resins. The polymerization reactions and kinetics of furfuryl alcohol and 2‐furyl ethanol into polymeric resins are detailed in this work. Nuclear magnetic resonance spectroscopy analysis of reaction kinetics, molecular weight analysis, and rheology analysis confirm that the polymerization reaction rate of 2‐furyl ethanol is much faster than that of furfuryl alcohol because the addition of this methyl group serves to stabilize the carbocation transition state. Side reactions, such as Diels–Alder crosslinking and in particular branching, are quantified and were found to be much more prevalent in the polymerization of PFA. The glass transition temperature was measured to be 376 K for PFA and only 294 K for poly(2‐furyl ethanol). Molecular dynamics simulations showed that the alternative structure that forms in PFA that causes branching results in greater backbone rigidity causing its higher glass transition temperature. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46608.

Three-Dimensional Micro- and Nanofabrication with Multiphoton Absorption

ABSTRACTMultiphoton absorption has become a powerful technique for the creation of three-dimensional micro- and nanostructures. Here we review some of our recent progress towards creating functional microdevices with multiphoton absorption. Specific thrusts of our research include development of new resins for multiphoton absorption polymerization, design of novel schemes for metal deposition, and post-fabrication ablation of polymeric structures.

APPLICATION OF NEURAL NETWORKS FOR THE DEFINITION OF THE OPERATING CONDITIONS OF FLUIDIZED BED POLYMERIZATION REACTORS

The development of polymer resins can benefit from the application of neural networks. The aim of this paper is to present how neural networks can help deal with the development of new resins, starting from the end user properties to set up the reactor's operating conditions. The procedure presented in this paper consists of a network that predicts the operating conditions of the reactor with maximum error of 2%. New resins can be developed and the reactor's operating conditions can be set in a much faster way, reducing the number of experiments and pilot plant tests, and hence, time and money spent on development.

Development of Polymer Resins using Neural Networks

The development of polymer resins can benefit from the application of neural networks, using its great ability to correlate inputs and outputs. In this work we have developed a procedure that uses neural networks to correlate the end-user properties of a polymer with the polymerization reactor's operational condition that will produce that desired polymer. This procedure is aimed at speeding up the development of new resins and help finding the appropriate operational conditions to produce a given polymer resin; reducing experimentation, pilot plant tests and therefore time and money spent on development. The procedure shown in this paper can predict the reactor's operational condition with an error lower than 5%.

New generation of long‐term stabilizers for polyolefins

AbstractPolyolefins are under evaluation for a variety of applications with increasingly stringent requirements, including long‐term exposure outdoors. While the range of physical properties and appearance has been extended by the development of new resins, additives are required to help maintain those properties upon exposure to sunlight, heat, and weather. The benefits of a new generation of light stabilizer with extraordinary efficiency in polyethylene (PE), polypropylene (PP), and other resins are discussed.

A study of the curing process of paint on metal utilizing thermal stimulated current (TSC) and relaxation map analysis (RMA)

The purpose of this work is to illustrate the use of the process of thermally stimulated current (TSC) for the analysis and control of crosslinking and curing of paints on metal substrates. The study of the crosslink density and/or cure ratio for paint on metal is vital, not only in the final quality inspection of a finished part, but also in the development of new resins and processes for paints and coatings.

Some Thoughts About Unsolved Physico-Chemical Problems of Composite Polymeric Materials

INTRODUCTION Substantial progress in understanding of the phenomena taking place at the interphase in composite polymeric materials has been made lately.1,2 The production industry of polymeric composite materials, i.e. polymers with dispersed mineral fillers and reinforced plastics with organic and inorganic fibers is nowadays very highly developed. Advent of the new types of reinforcing fibers—carbon, boron, high-modulus and heat-stable synthetic fibers—along with successes of chemistry in the development of new resins has made possible the solution of a number of important technical problems. However, as a rule, these solutions are not based on clearly established mechanisms of the processes taking place at the interphase between the two components, although these phenomena determine the most important physical and mechanical properties of the compositions, and although the interphase is the region whose properties in large measure control the properties of the material. Despite a great number of works in this field there still exist many unsolved problems. Discussion of some of them is the subject of the present paper.