Use Of Resin Research Articles

Compounds based on ultra‐high molecular weight PVC resins for use in automotive applications

AbstractThis paper reviews early work done in Japan and leads into recent domestic activities reviewing the current “state of the art.” The authors present original work covering the development of elastomeric PVC compounds for interior and exterior automotive compounds. Compound variations include variations in the molecular weight of the speciality resin component, effect of plasticizer level changes, and the addition of alloying polymers. Physical characteristics such as hardness, specific gravity, torsional modulus, tensile strength, elongation, compression set, and abrasion resistance are measured and reported. Rheology of the compounds are characterized and related to processing ease and compound surface characteristics, smoothness, gloss, etc., and evaluated in light of potential automotive applications. Weatherability for use in automotive exterior trim is discussed.

Diagnostic Immunoelectron Microscopy in Surgical Pathology: Assessment of Various Tissue Fixation and Processing Protocols

We have investigated various tissue fixation and embedding protocols in an effort to allow expanded use of immunoelectron microscopy in diagnostic surgical pathology. A sample of normal human small bowel mucosa was processed using seven different methods for subsequent postembedding localization of chromogranin A. In addition, several archival cases of neuroendocrine tumors previously fixed and routinely embedded for electron microscopy, stored in formalin, or snap-frozen were retrieved and variously processed for chromogranin A localization at the ultrastructural level. Precise localization of chromogranin A in dense core granules was achieved with protein A-gold on sections from all of the processing methods. The methods included retrieval into mild fixative of previously formalin-fixed or snap-frozen tissues followed by embedding in Lowicryl K4M (Polysciences Ltd., Eppelheim, Germany). Thus, tissue processed without foresight of the need for immunoelectron microscopic localization can be successfully used. Since embedding of tissues in Lowicryl K4M has been shown to preserve a variety of antigens, it may prove to be a superior resin for use in diagnostic immunoelectron microscopy.

Fracture Behaviour of Thermoplastic Modified Epoxy Resins

Abstract This work has shown that the addition of polyetherimide (PEI) can significantly increase the toughness of highly cross-linked epoxy resins, whilst retaining a high Tg and modulus. These combined properties indicate the potential of PEI modified epoxy resins for use as matrices for advanced composite materials. In terms of GIC, addition of 20wt% PEI raised the toughness by a factor of eight. Evidence from SEM fracture surfaces suggests that the toughening mechanism operating in bulk PEI modified epoxy resin is ductile drawing of the PEI. Carbon fibre composites based on 30wt% PEI modified epoxy resin matrices show considerable improvement in toughness at low and high strain rates when compared with CFRP possessing unmodified or 20wt% modified PEI content epoxy resins.

Fracture behaviour of toughened epoxy resins cured with N, N′-dimethylethylenediamine

Two series of toughened epoxy resin systems, which are models of matrix resins for use in carbon fibre reinforced plastics, were prepared. Evaluations of the cured epoxy resins, measuring fracture toughness, impact properties, tensile properties and dynamic mechanical properties were conducted. The correlations between these properties and the apparent concentration of network chains in the resins, v, were investigated and the fracture surfaces were examined with a scanning electron microscope. The superior toughness of these resin systems was obtained without considerable loss in modulus. Unified maximum peak was observed in the plots of Izod impact strength, where the v value of the cured resins was increased.

Interpenetrating polymer network approach to tough and microcracking resistant high temperature polymers. Part II. LaRC‐RP41

AbstractRecently, we reported on the interpenetrating polyimide network (IPN) approach to develop tough and microcracking resistant high temperature matrix resins for use in aircraft/aerospace structural components. One such polymer developed is designated LaRC‐RP40. This new simultaneous semi‐IPN was prepared from easy‐to‐process but brittle crosslinking PMR‐15 and tough but difficult‐to‐process linear NR‐150B2. Significantly improved toughness, microcracking resistance, and glass transition temperature over PMR‐15 were realized from the combination. These property improvements were achieved without compromising ease of processing, high temperature mechanical performance, and cost effectiveness compared to PMR‐15. These results encouraged us to further explore this approach for the development of a wider range of polymers of basic technological and economic interest. In the present work, we combine crosslinking PMR‐15 and linear LaRC‐TPI to provide a new sequential semi‐2‐IPN called LaRC‐RP41. The physical and mechanical properties of the neat resin and composite reinforced with graphite fibers are presented. The phase morphology and phase stability of the neat resin and composite studied by various techniques are also discussed.

Mechanical properties of heat treated restorative resins for use in the inlay/onlay technique

Inlay/onlay materials based on composite resins have recently been introduced. It was the aim of the present study to investigate the effect of post-curing temperature on selected mechanical properties. Four different composite resins were produced. The composite resins had identical filler content, but varied with respect to the content of the monomers BISGMA, TEGDMA, UEDMA, and HEMA. After initial curing by light, the materials were post-cured at 37, 100, 125, 150, 175, or 200 degrees C for 1 h. We then measured diametral tensile strength, flexural strength, and modulus of elasticity. These properties were found to vary with the composition of the material. Composites containing UEDMA or UEDMA/HEMA were stronger and stiffer than BISGMA/TEGDMA formulations. The optimum post-curing temperature was 150 degrees C, but the increase in strength and stiffness was moderate, only about 9%.

INPAINTING USING PVA MEDIUM

AbstractThirty-seven years ago, Mario Modestini, Chief Restorer of the Samuel H. Kress Collection, set out to adapt modern synthetic resins for use in retouching. In collaboration with the National Gallery of Art in Washington DC, a testing project was carried out and polyvinyl acetate (AYAB) was chosen, because its low glass transition temperature promised longevity of the restorations. In addition, PVA could be dissolved in alcohol or acetone, some of the least harmful solvents for the health of conservators. A description of the technique is documented by photograph from the studios of both Mario Modestini and the present author.

A Fundamental Approach to Resin Cure Kinetics

Thermoset polymer resins are an important class of materials, particularly when used as the matrix for advanced fiber composites. Because material performance is directly related to processing, it is useful to study the cure kinetics of these resins for use in process modeling, design and control. Several workers have attacked this problem using empirical rate laws. However, a fundamental approach can offer more flexibility without being cumbersome or impractical. In this work, amine-catalyzed epoxy reactions are studied. A kinetic model is developed and applied to experimental data from the literature, as well as from our laboratory. We show that this model is able to describe the cure reac tions of "real-world" systems, and unlike the empirical rate laws, can account for variations in the resin formulations.

Preparation and use of latex-coated resins for anion chromatography

A procedure is described for the preparation of low-capacity anion-exchange resins for use in single-column ion chromatography. The resins are prepared by hydrophobically coating an anion-exchanging latex onto unfunctionalized resins made by Rohm & Haas. The resin exchange capacities are varied by changing the concentration of the sodium chloride or latex in the coating solution. Various resin matrices can be coated and capacities from 5 to over 400 μ equiv./g are obtained. The mechanism of latex adsorption is discussed and several highly efficient anion separations are presented.

Liquid dropping resin for IC encapsulation

One method to encapsulate bare ICs on an organic substrate uses liquid epoxy resin. A type of liquid epoxy resin for use in tape automated bonding plastic leaded chip carrier, plastic-base pin grid array, and IC card is discussed. Epoxy resin used for this purpose should be of high reliability, comparable to that of the monolithic ICs which had not been realized on conventional resins used for chip-on-board applications. In order to meet these requirements, the characteristics of resin which yield high reliability, and methods to improve these characteristics have been studied. Effective factors which had been found to contribute to higher reliability are discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The homogeneity and radiation sensitivity of a calcium-containing low-viscosity resin for use as a standard in analytical electron microscopy

The availability of good elemental standards is essential for the quantitative analysis of soft biological tissues. A standard that contains a homogeneous distribution of the elements of interest, has a high level of stability in the electron beam, and models the specimen in chemical composition would be an ideal case. We are involved in a continuing investigation examining both the homogeneity and the radiation sensitivity of a set of prepared standards. Here we report the initial results, with regard to calcium distribution within, and radiation sensitivity of, a calcium containing low viscosity epoxy resin.Calcium Naphthenate was incorporated into Spurr's resin using a protocol given by Simon (personal communication), from concentrations of 30 millimoles of calcium per kilogram of resin to l00mm/kg of resin.

PMR-15 processing, properties and problems—a review

The frontrunner in the race to develop a high temperature resin for use in advanced composites intended for high temperature applications is the NASA developed polyimide PMR-15. One of the key factors in the success of the material is the relatively easy processing which is due mainly to the use of the PMR approach (Polymerisation of Monomeric Reactants). Prepreg and high quality composite laminates (glass or carbon) can be prepared with ease. Laminate properties compare well with conventional epoxy based systems but thermal stability is much greater. Continuous use temperatures are in the range 280-300°C, some 150-170°C higher than epoxy systems. Applications of PMR-15 composites include aero-engines, missiles, spacecraft and military aircraft. Despite being the leading system available today PMR-15, like all materials, has a number of limitations affecting its widespread use. Included in these are reliable methods of quality control, prepreg batch to batch variability, microcracking from thermal cycling, health and safety hazards and high temperature processing. This paper reviews the present status of PMR-15 development and outlines work designed to identify and where possible overcome these limitations.

Fluorescence spectra and lifetimes of several fluorophores immobilized on nonionic resins for use in fiber-optic sensors

Spectres d'emission de fluorescence et duree de vie d'echantillons de 0,01 a 1,0 mM de rhodamine B, rhodamine 6G, eosine Y et fluoresceine adsorbes sur des resines XAD-2 et XAD-4. Comparaison entre fluorophore lie et en solution. Ces systemes sont utiles dans les detecteurs a base de fibrooptiques

Preparation of sulfonated gel resins for use in ion chromatography

Conditions are studied for reproducibly sulfonating small, spherical poly(styrene-divinylbenzene) beads to obtain cation exchangers suitable for ion chromatography. The effects of wetting agents and sulfonation parameters are noted. Resin capacity is examined as a function of crosslinking under fixed sulfonation conditions. Sulfonated resins of the highest crosslinking studied (12%) are shown to be very efficient for ion chromatography. Electron-photomicrographs show that sulfonization occurs only on the outer surfaces of the spherical beads.

A specimen holder to enable larger tissue samples to be processed automatically to resin on the Sakura electron microscope processor (Model REM-20B).

Described is a specimen holder to be used as an accessory to the Sakura Electron Microscope Processor (Model REM-20B). It permits tissue samples up to 1.5 cm in length to be processed automatically to resin for use in light microscopy. The device can be easily made by any small workshop equipped with a lathe.

New raw materials and new equipment for printing ink manufacture

Cray Valley Products Ltd., St. Mary Cray, Orpington, Kent, BR5 3PP, have recently introduced a range of resins for use in liquid inks. This range consists of Unithane 672S, Synaqua 845S, Synaqua 846S and Versamid 790.

A Tree Growth Inhibiting Insulation for Power Cable

This paper describes a power cable insulation with a tree growth inhibiting additive that is nowommer commercially available for use by the electric utilities. The new insulating resin inhibits the growth of both electrical and water trees. A major cause of insulation failure is the progressive ive degradation process called treeing. There is general agreement that electrical and water trees cause insulation degradation leading to cable failure. This paper deals with a thermoplastic polyethylene insulating resin for use in power cable systems. Dodecanol is added to polyethylene to inhibit the growth of both electrical and water trees. The differences between electrical and water trees are reviewed. Test methods for evaluating insulating compositions for resistance to electrical and water tree growth are presented using small laboratory samples in accelerated tests. Data obtained in special model cables show the extent of migration of the dodecanol in accelerated tests. Test results on full sized commercial cables are discussed.

Adhesive bonding of various materials to hard tooth tissues: XXIII. Isotonic monomer formulations.

With regard to adhesion to dentin by chemical mechanisms, the vitality of odontoblasts and contiguous pulpal cells might require that materials influencing the dentinal tubules be maintained within certain limits of osmotic pressure. Resins for use in adhesive formulations can be made isotonic with vital tissues by adjusting the proportions of hydrophilic monomers and the water contents of the formulations.

Mixing of polydisperse particles in the fluidized bed of a multisection apparatus

In practice, however, we have to deal with a polydisperse ion-exchange resin having particle dimensions in the range from 0.I to 2.5 mm. In the preparation of the resin for use, i.e., in washing and regeneration, its particles having dimensions smaller than 0.25 mm are removed from the apparatus by entrainment and, as a rule, the operation is performed on particles of 0.25-2.5 mm polydisperse fraction. In view of this, the necessity arises for investigating the mixing of a polydisperse mixture of particles in a continuous multisection apparatus.

Recent progress on urethane resins

An important development in the urethane coating area is the use of polyisocyanates, in combination with hydroxylated acrylic resins, to provide room‐temperature‐curing coatings. These new formulations, according to Klein and Elms [Journal of Paint Technology, 43, November (1971) p. 68], demonstrate lightfastness, good outdoor durability and solvent resistance when the acrylic resin is coreacted with an aliphatic polyisocyanate. The acrylic resins are copolymers which contain either the hydroxypropyl or hydroxybutyl ester of acrylic or methacrylic acid as one component. Hydroxypropyl acrylate acetoacetate extends the potlife of this two‐component coating. The authors describe work in which glass transition temperature is used as a means for selecting the correct hydroxylated acrylic resins for use in the system. If the glass transition temperature is between 22 and 54°C, a flexible coating with good impact resistance results, but the system requires baking. At a glass transition temperature of 54° and a hydroxyl value of 26, a composition results which dries rapidly at ambient temperatures and which provides good hardness and mar resistance. The coreactant in this instance is an aliphatic diisocyanate composition based on hexamethylene diisocyanate.