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Reviews the traditional use of thermoset (epoxy) adhesives for various bonding applications and highlights some limitations in today’s microelectronics arena. In particular, concerns for thermal and stress management associated with large area silicon bonded to a wide variety of substrate materials has led to an increasing interest in thermoplastic adhesive technology. Thermoplastics are not always the best solution for every application. This paper sets out to address the “pros and cons” of each polymer technology for different microelectronic applications taking into account some of the key physical properties such as Tg, TCE and modulus. In addition, practical issues such as handling, storage and processing are considered in detail.

To produce a coated fabric, a base fabric may be completely or partially coated with a polymer layer, which changes the properties of the new system relative to the base fabric. The purpose of this paper is to analyze the influence of the thermal transfer material and its shape on the deformability of knitted fabrics during the uniaxial extension and to determine the residual deformation of the thermoplastic transfer element of coated fabrics after unloading.

Knitted fabrics were partially and entirely coated with heat transfer material. For partial coating, square pieces of three different transfer materials were bonded on the middle of the specimen. They were solid, perforated with either nine circular holes or six rectangular holes. A heat seal press was used to laminate knitted fabrics. The samples were subjected to uniaxial tensile testing. The characteristics such as strain at maximum force, strain at break, and strain at low stress were measured. After stretching and relaxation of the specimens, the residual deformation of the heat transfer element was also investigated.

The results indicated that coating knitted fabrics with transfer material may decrease their stretchability. The experiments show that the decrease in stretchability and in the degree of residual deformation after stretching and relaxing depend on the knitted structure, the shape of the transfer element, and the degree to which the fabric is coated.

This study examines the influence of heat transfer material which may be not only entirely but also partially joined with knitted fabric layer on the deformability and shape stability of this system.

SPECMAT LTD of Leominster, Herefordshire, has won an order worth £1.7 million from the US Air Force to supply high‐perfoimance radomes for its Hercules transport aircraft.

Drynamels Ltd., a T.I. company and specialist in the manufacture of coatings for metal surfaces, has recently concluded an agreement for the exclusive rights in the U.K. for the Oxyplast range of epoxy powders developed by Libert Freres, of Ghent, Belgium. In this article the technical director of Drynamels describes the step forward in powder coating technology represented by this development.

This paper reports on the development of a simple manufacturing process for polymeric multilayer substrates utilising the thermoplasticity of thermoplastic resin. Features and defects noted in manufacturing trials of the substrates are also reported. The process involves a polymer‐based thick film conductive paste screen printed on a hole‐punched thermoplastic resin film and dried. The films are stacked to form multiple layers and are then compressed into one unit. As the extremely thin thermoplastic resin film layers are equivalent to a single layer, a feature of this substrate is its exceptional thinness. As thermoplastic resin is used as a base material, the soldering process and other connecting technologies which may be used in place of solder connection are also examined.

Today’s emerging markets in the electronic packaging industry require some unique properties in adhesives, especially in die attach applications. In multichip module (MCM) applications, for example, the low temperature reworkability of die bonds is of primary importance, particularly if known good die (KGD) are not employed. If KGD are used in the MCM, a temporary, reworkable die adhesive is also desirable for a KGD testing programme. Large area die on organic substrates, which are key to the more portable, high power computers, require a very compliant adhesive to absorb the high mismatch in expansions. An overview of the present adhesive technologies reveals some serious limitations in their application and performance. Traditional Ag epoxies, primarily because of their irreversible ‘thermosetting’ during cure, do not fulfill all the material requirements. Thermoplastic chemistries are ideal candidates for MCMs because of their reversible melting and resolidification properties. This paper details the development of a novel silver loaded thermoplastic paste that overcomes most of the deficiencies seen in present day adhesives. One of the main obstacles that has hindered the use of thermoplastic pastes as an adhesive has been the slow solvent extraction during the curing step. With current technology, this inherently slow solvent extraction typically requires a complex process of first depositing a flat profile, then removing the solvent with a pre‐drying step, and finally attaching the die by a heat/pressure step. A blend of components, hereafter referred to as DM4030, has been tested and compared against conventional materials in the industry. Functional properties of adhesion, resistivity, wire bonding and others are summarised for various temperature profiles. Long‐term reliability test results are shown for temperature cycling, temperature/humidity (85° C, 85% RH), and high temperature storage. For reworkability applications, die removal force as a function of temperature is also presented.

The purpose of this paper is to elucidate the aging effect in dye-sensitized solar cells (DSSCs) sealed with thermoplastic film and to compare it with unsealed DSSCs.

The paper presents the steps of the fabrication of standard DSSC, as well as the DSSC-sealing processes, by using thermoplastic film. Current-voltage characterization was performed to observe the changes in efficiency, fill factor, short circuit current density and open circuit voltage for both unsealed and sealed DSSCs for aging time up to 336 h.

The unsealed DSSC showed significant drop in efficiency from 4.26 to 2.42 per cent within the first 5.5 h of aging time because of the leakage and volatilization of the solvent in the electrolyte. On the other hand, the sealed DSSC exhibited a gradual improvement of efficiency from 4.16 to 4.73 per cent after the first 216 h of aging time. The initial efficiency increment can be ascribed to the improved adsorption of electrolyte into the titanium dioxide film because of the gradual desorption of excess dye from TiO2 with increasing aging time.

This paper demonstrates the importance of the proper sealing process for the long-term operation of DSSC.

This study aims to present that the chemo-responsive shape recovery of thermoplastic polyurethane (TPU) is tunable by solvents with different solubility parameters, and it is generic for chemo-responsive shape-memory polymer and its composites.

Two kinds of commercial TPU samples with different thicknesses were prepared by panel vulcanizer and injection molding (an industrial manner) to investigate their chemo-responsive shape memory properties in acetic ether and acetone.

Results showed that all of TPU films with different thicknesses can fully recover their original shapes weather they recover in acetic ether or acetone. But the recovery time of TPU films in acetone is greatly reduced, especially for the twisting samples. The residual strains of recovery TPU samples after extension reduce obviously.

The great decrement of recovery time is related to two factors. One is due to the bigger solubility parameter of acetone with higher dipole moment compared with those of acetic ether, and the other is the remained internal stress of TPU films after preparation. The internal stress is identified to have an effect on the shape-memory properties by comparing the recovery process of samples with/without annealing. The reduced residual strains of recovery TPU samples after extension is due to the increasing mobility of polymer segments after molecules of acetic ether penetrates into the polymeric chains.

This is a universal strategy to control the recovery process of shape-memory materials or composites. The underlying mechanism is generic and should be applicable to chemo-responsive shape-memory polymers or their composites.

The aim of this study was to evaluate the feasibility of pad printing for producing electrical conductors and to define the factors affecting the print quality of polymeric silver ink conductors.

Polyethylene terephthalate (PET) film and polyphenylene oxide (PPO) compound film were used as substrate materials. Three different polymeric silver inks, marked A, B and C, were used and tested.

The results indicated that the important factors in the pad printing of silver ink conductors are the printing parameters and characteristics of the ink, pad, cliché and substrate. The interactions of these factors should be considered on a case-by-case basis. The sheet resistances of triple-pressed ink conductors varied between 20 and 110 mΩ/sq for 5.7- to 8.5-μm-thick conductors. Ink (B) had a higher sheet resistance than Ink (A) because of its lower silver particle content but also because of the shorter curing time and lower curing temperature. Ink (A) showed excellent adhesion on PET, and Ink (B) had moderate adhesion on PET without corona or plasma pre-treatments, but both inks adhered weakly on PPO compound. Both corona and plasma treatments raised adhesion of these two inks on all test substrates to the highest classification value, 5B.

This paper contains a survey and preliminary testing of the pad printing of polymeric silver ink conductors on flexible thermoplastic foils. Finally, the paper introduces the advantages and drawbacks of the technique.