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The Chemical And Physical Properties And Mechanical Relaxation Of Electroless Copper Plating Poplar Composites

Posted on:2016-08-17Degree:DoctorType:Dissertation
Country:ChinaCandidate:J QinFull Text:PDF
GTID:1221330482481944Subject:Wood science and technology
Abstract/Summary:PDF Full Text Request
In order to analysis the chemical and physical properties and mechanical relaxation phenomena of copper plated poplar veneer composite, and provide the basic theory and technical parameters for the research and application of the geothermal floor substrate, the crystal structure、the surface chemical structure, the electrical conductivity、the thermal conductivity、the electromagnetic shielding and the mechanical properties such as hygroexpansion、the creep properties and the stress relaxation are studied through the method of XRD、XPS、NIR spectra and mechanical relaxation and so on in this dissertation.Research results are summed up as follows:1. The Cu diffraction peaks observed in the XRD spectra of the copper plating poplar veneer which is cubic structure. The crystal of cellulose was changed to a certain extent and covered by copper layer because of the chemical substances in chemical copper plating.2. XPS spectra show that Cu is in the presence of Cu2+ in the single plate copper plating of poplar. The disproportionation of Cu+ tends to be completely when CuOH and Cu2O gradually reduced to metallic Cu with the extension of the plating time. The reaction of Cu20 and CuOH gradually complete when the plating time reached 25min.3. The electromagnetic shielding of electroless copper plating poplar veneer can reach 100dB within the range of 800-1200 MHz, which is belong to the reflective electromagnetic shielding material. The volume resistivity of structure A which is the composition of single plate and electroless copper plating veneers is less than structure B which is the composition of electroless copper plating veneer. The thermal conductivity of structure A and B is more than 2 times higher than structure C which is the compotion of single plating veneers under the condition of the same moisture content and the thermal conductivity is increased with the extension of plating time.4. The dry shrinkage rate of length and width direction of material A/B/C is changed between 0.1%--0.6% and the dry shrinkage rate of thickness direction is 5-7 times the length and width directions at constant changing of temperature and humidity cycles. The two curves always deviate from the same equilibrium state, so that the end of the curve of the change of the desorption water content is always higher than that of the curve of the change of moisture content because of the superposition effect of continuous non equilibrium state. The equilibrium moisture content of structure B is higher than that of structure A and C in the process of moisture absorption.5. In the process of continuous moisture absorption and desorption, the creep deflection of three kinds of electroless copper plating poplar composites are all increased which correspond with general rules of mechano sorptive creep of wood materials. The creep resistance of structure A electroless copper plating poplar composites is better than structure B and structure C. The copper plating and proper structure can inprove the creep resistance ability of electroless copper plating poplar composites.6. The relative stress relaxation of structure D、E and F tends to change slowly with the increase of the joint size.The relative stress appears the trend of structure D> structure E> structure F in the same temperature because of the water swelling increase of structure D which is single plate composites. The stress relaxation of structure F is slow due to the barrier of the surface of copper plating layer. The stress relaxation of structure E changes in the middle because of the combination of single plate and copper plating.
Keywords/Search Tags:electroless copper plating composites, electrothermal conductivity, dry-wet effect, creep, stress relaxation
PDF Full Text Request
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