Plate Curing Research Articles

Joining of PP/EPDM TPV to aluminium alloy 6061-T6 directly via generating sorbate in situ and adjusting the heat input of welding

At present, it is difficult to join the non-polar thermoplastic vulcanization based on Polypropylene (PP)/Ethylene-Propylene-Diene (EPDM) to aluminium alloy 6061-T6 (A6061) directly because of the great difference in physical and chemical properties between them. In this paper, zinc sorbate (ZDS) was introduced into the dynamic vulcanization process of PP/EPDM TPV to achieve high performance TPV interface modification. The results show that the polymerization of ZDS can enhance the interface compatibility, melt strength and surface energy of PP/EPDM/ZDS TPV while reducing the linear expansion coefficient of TPV. On this basis, the plate curing machine is used to simulate friction stir welding, and the heat input (temperature:180 °C, pressure:20 MPa, welding time:60 s) was optimized. PP/EPDM/ZDS TPV was directly connected to A6061, and the influencing factors of the joint strength were analyzed. The results show that the tensile shear strength of composite joints decreases with the static time and then keeps stable, reaching 3.53 MPa. The chemical bond (Al-C) is formed at the interface between A6061 and PP/EPDM/ZDS TPV, which plays a key role in improving the strength of the joint. The results of this work can expand the application range of PP/EPDM TPV, and provide basic data and theoretical support for the connection between TPV and metal.

Effect of graphite nanoplatelets percentage on the in plane thermal diffusivity of ultra-thin graphene based (nanostructured) composite

The increasing demand for high-performance materials in thermal management has focussed the attention on new materials like graphene/graphite paper. These materials offer a unique combination of properties, such as: high electrical and thermal conductivity, high thermal diffusivity, they are flexible, lightweight, good mechanical properties and, sometimes, cost-effective. However, compared to traditional materials, their thermal characterization is more complex. Consequently, it is important to develop and assess both low-cost techniques for GNP composite paper production, as well as procedures to measure their thermal properties. In the present work, graphite nanoplatelets composite (GNPs composite) with different GNP content (in the range 70–100%) were adopted for the production of thin foils (50–70 µm in thickness) by solvent impregnation techniques, followed by hot plate curing. Spatially Resolved Method (SRM) technique was adopted to measure the in-plane thermal diffusivity of the composites. Tests were carried out adopting a diode laser as a heat generator and an IR camera to acquire the temperature distribution after heating. Two different procedures were adopted: in the first, the samples were coated by a radiation absorbent paint, with a known emissivity. The second one involves the use of the “as-received” samples and their actual emission coefficient. ANalysis Of VAriance was adopted to discriminate the effect of the radiation absorbent coating and the GNP content. From the results, the SRM technique is an effective method for the measurement of in-plane thermal diffusivity of ultra-thin GNP composites. The latter varies in the range 33–87 mm2/s, according to the GNP content.

Value of Concrete Compressive Strength on 28 days with Variation of Candlenut Shell Applicated to Plate on a Non-destructive Test Using Hammer Test

Concrete compressive strength is one of the parameters used to control the quality of a concrete. Concrete compressive strength testing method which is considered the highest level of reliability is a destructive test using a compressive testing machine. Testing requires quite high costs and a longer processing time. But sometimes testing must be done in the scene. Based on the case, a testing tool is needed to measure or determine the compressive strength of concrete without spoil, which is known as the non-destructive test. The tool commonly used for this test is the hammer test. The type of research is experimental. The purpose of this research is to get the compressive strength value of a concrete plate variation of 30% candlenut shells from the test results using a hammer test so as the results can be close to the results of testing using a compressive testing machine (destructive test). The research variable is the testing method (3 point of testing with angle 0°), the age of concrete plate curing, the method of curing (wet curing and dry curing). The number of samples of reinforced concrete slabs is 8 pieces measuring 50cm x 25 cm x 12cm. The research results are Compressive strength of concrete slabs of 30% candlenut shell variations using a Hammer test showed that the concrete strength reached 23-27 Mpa both in wet curing and dry curing or equivalent to the quality of K250 concrete at 28 days. The results also indicate higher values compared to normal concrete slabs.

The Effects of Processing Parameters and AC Foaming Agent on the Mechanical Properties and Morphology of Foamed Wood-Polylactic Acid (PLA) Composites

Wood flour, PLA, and other additives were mixed evenly in a high speed mixing machine. The granules were prepared by melt blending and extrusion granulating with a twin-screw extruder, and test specimens were molded by a plate curing machine. By changing the heating temperature, the molding pressure, the holding pressure time, and azodicarbonamide (AC foaming agent) contents, the influences of four factors on the apparent density, the mechanical properties, and the morphology of the biodegradable foamed WPCs were investigated. The best processing parameters and the optimum AC foaming agent content were obtained. When heating temperature was 178 °C, heating time was 10 min, holding pressure time was 25 s, and molding pressure was 7 MPa, the test specimen was lighter in color, with a smooth surface and dense, uniform cross section. The mechanical properties (flexural strength and impact strength) of the foamed WPCs were relatively good. When adding 1% AC foaming agent, the foamed WPCs showed uniformly distributed microcellular structure, and the average pore diameter was about 67 µm. The density was reduced by 18.6%, and the flexural strength and impact strength were increased by 128.6% and 40%, respectively, compared with non-foamed WPCs.

Morphology and surface characteristic control of dimpled wrinkles using microscale water-soluble powders

We proposed a novel method for the morphological shape change of dimpled wrinkles using water-soluble powders to modify surface characteristics. Ultraviolet (UV)-curable resin was coated thinly on an aluminum plate and three water powders with 70, 100 and 200 μm in average diameters were dredged on each resin-layered plate. After a short exposure in UV light for less than 15 s on the plate and subsequent thermal curing, we observed microscale wrinkles with diverse morphological structures. Next, dimpled wavy structures were observed by dissolving water-soluble powders on the skin using water rinsing. Through experimental results, wrinkle morphology was affected by the powder size and resin layer thickness. Using this simple approach, various types of dimpled wavy structures can be realized and may be utilized in engineering applications, such as hydrophobicity control.

Comparison of Thermal Properties of PCB Photoresist Films Cured by Different Techniques

The possibility of implementing microwave technology to photoresist film curing which is a major process in the production of electronic printed circuit boards (PCB) was investigated and compared with a conventional curing method, e.g. UV lithography. Since both techniques involved irradiation, hot plate curing which relies on thermal conduction was undertaken to study the effect of a heat transfer approach. Two film thicknesses were studied, i.e. 0.0012 and 0.002 inch, and the effects of curing power and time were investigated. Thermal properties, i.e. percent cure, glass transition temperature (Tg), composition and degradation temperature (Td), were evaluated using a Differential Scanning Calorimeter (DSC) and Thermogravimetric Analysis (TGA) and it was found that the commercial UV irradiation was sufficient to completely cure the thin film but only reached 76% cure for the thicker film, resulting in a lower Tg. The results show that the required processing conditions using a conventional household microwave to obtain almost complete curing were 1,000 Watts and 10 minutes curing time. In addition, improved curing was achieved in the thicker film because microwave can transmit into polar materials whereas UV cannot penetrate very far into the material. The hot plate curing was observed to produce a higher degree of curing and Tg, however, the uniformity of heating was found to be a major limiting factor of this technique. Slight differences in decomposition profiles of the films cured by different techniques implied slight differences in molecular structures. Compared to UV and hot plate curing, microwave technology was demonstrated as a potential curing technique in the production of PCBs due to its ability to efficiently cure thick films resulting in a strong material with high Tg. To apply the technique to other processes, optimal conditions, i.e. power and time, should be further investigated as well as the prevention of hot spots.

A novel cureless pure lead oxide plate for valve-regulated lead-acid batteries

Pure lead oxide has been tested as a starting material for VRLA lead-acid batteries. The influence of the acid- to-oxide ratio and the paste density on the plate formation and battery performance has been investigated. The results show that the plates can be directly formed without undergoing the conventional plate curing process if pure lead oxide is used. The new process shows significant advantages in simplifying the conventional plate making processes for lead acid batteries and reducing the production cost and time.

Influence of paste composition and curing program used for the production of positive plates with PbSnCa grids on the performance of lead acid batteries

The cycle life performance of lead acid batteries with PbSnCa grids is strongly affected by the structure and properties of PAM and of the interface PAM/grid. The latter interface is formed during curing and formation of the positive plates. The processes that take place on curing of positive lead acid battery plates produced with Concast or Conroll PbSnCa grids and 3PbOPbSO 4·H 2O (3BS) or 4PbOPbSO 4· xH 2O (4BS) pastes are discussed in this paper. The enhanced processes of Sn and Ca segregation in the alloy of the grids during plate curing lead to the formation of a thin layer of a new phase, composed of the intermetallic compound (Pb 1− x Sn x ) 3Ca, in the spaces between the metal grains or sub-grains. This layer makes the interface heterogeneous and exerts a detrimental effect on the cycle life of the battery. In order to suppress its effect on battery performance, the thickness of this layer should be reduced by reducing the content of Ca in the grid alloy. During plate curing, the heterogeneous surface of the grid alloy is oxidized under the action of oxygen and H 2O at elevated temperature and the alkaline solution in the paste pores. A corrosion layer is formed comprising a thin sub-layer (CL1) and a thick partially hydrated lead oxide sub-layer (CL2). The 4BS/CL2 contact surface is larger and more stable than that between the 3BS particles and the CL2 layer. Both 3BS and 4BS particles are bonded to the CL2 layer through their hydrated layers. When curing is conducted at temperatures above 80 °C, 3BS particles are converted into 4BS ones which contain water. It has been established that positive plates produced with 4BS plates cured at 50 °C have the longest cycle life and adequate capacity performance, but a bit low power output. Positive plates prepared with 3BS pastes, which are then converted into 4BS ones during plate curing at 90 °C, have high initial capacity and power performance, but shorter cycle life. Batteries with plates produced with 4BS pastes and then cured at 90 °C for less than 4 h have both satisfactory power output and cycle life. The obtained results indicate that the conditions of positive plate curing exert a strong influence on the performance of batteries with PbSnCa grids.

Beneficial effects of red lead on non-cured plates for lead-acid batteries

In order to find a more convenient processing method and more suitable paste formula for making VRLA batteries, hydrogen peroxide solution and red lead (Pb 3O 4) have been used together during the paste preparation. The use of hydrogen peroxide solution to replace the conventional sulphuric acid solution can accelerate the oxidation of free lead in the paste and therefore reduce the time for the plate curing, while the addition of red lead can enhance the cell formation and improve the cell performance. Based on these two beneficial functions, a new process for making VRLA cells was proposed and investigated. Cells were assembled directly from freshly pasted plates without undergoing the conventional plate curing and drying process, and the battery formation that followed was successful. The new processing resulted in an increase in the production efficiency and a substantial reduction in production time and cost. The battery performance, in terms of both the initial discharge capacity and the cycle life, is also improved by the use of red lead.

Aspects of lead/acid battery manufacture and performance

In keeping with previous Asian Battery Conferences, the meeting closed with an expert panel of battery scientists and technologists answering questions put by the delegates. The subjects under consideration were: Leady oxide production: choice of process; effect on paste mixing and plate curing. Paste mixing: temperature control; red-lead addition; paste degradation; expander addition. Plate curing: hydrocerussite formation; effect of oxide variety; tetrabasic lead sulfate. Plate formation: soaking time; acid sp. gr.; difficulties with negative plates. Battery performance: influence of depth-of-discharge; problems with perchloric acid; the memory effect; magic potions.

Aspects of lead/acid battery technology 8. Battery oxide

The basic component of present-day lead/acid battery active materials is a high metallic lead oxide that is made in attrition mills or Barton pots. The composition of this material dictates the process of plate manufacture and confers to the active materials a particle-to-particle bonding from which stems material strength and service life. The operation and control parameters of attrition mills and Barton pots are described. The level of free lead in the oxide dictates the vigour of the subsequent plate curing reaction and the time interval over which a paste remains usable.

Aspects of lead/acid battery technology 3. Plate curing

Curing is the process by which strength and adhesion of paste to grid is established prior to formation. The conditions for effective curing are set out and the two basic methods, fast and slow curing, described together with problems associated with curing. The introduction of a curing stage may be necessary with tubular positives where some filling powder blends are used. Unless the free lead in the filled plate is reduced there can be a significant self-discharge in charged, fresh cells awaiting delivery.

Towards improved manufacture of lead/acid batteries — panel discussion

During the Fourth Asian Battery conference panel session, topics under discussion were as follows. Alloy and grid technology: analysis of alloy composition; grain refiners; very-low antimony alloys; cracking of cast grids; strap alloys; cast-on strap process; inter-cell welds. Separator technology. Plate processing: oxide production; paste mixing; plate curing; dry-charging. Battery performance: JIS endurance test; overcharging; hydrogen sulfide generation; thermal runaway; grid corrosion; failure modes.

Relative-Humidity/Temperature Relationships for Saturated Salt Solutions: Application to Lead/Acid Plate Curing

Relative-Humidity/Temperature Relationships for Saturated Salt Solutions: Application to Lead/Acid Plate Curing