Papers by Keyword: Polymer Material

Abstract: The present work investigated the variation of internal structure, molecular orientation, crystallinity and mechanical characteristics of polypropylene(PP) after rolling process. The materials plate became narrow when rolled from entrance to exit, and the internal crystalline gradually deformed and at last destroyed. Plastic deformation was discovered along the rolling direction. In this direction, the crystallinity and vickers hardness were decreased, and molecular orientation was increased. Moreover, molecular orientation had a sharp increase at the second half part of rolling sample. The tensile stress of rolled samples increased by 80% parallel to rolling direction and decreased by 22% perpendicular to rolling direction.

Abstract: In this paper, for the transference phenomenon of high polymers, a method of measurement system based on sodium light and feisuo interference with digital image processing technology was proposed. At first, the system measurement scheme and method were explained and there were some experiments with micro moleculesIn the experiment, the high polymer is the mixture of acetone and organic glass by a certain ratio, the micro molecules are Acetone and ethanol; at last, the interference strips were collected at interval time by using the image control collection procedure and processed. After thinning the fringes, we calculated the fringe spacing distance by K-L transform, by measuring the fringe spacing change in the polymer transference of acetone and ethanol we draw the change rule of the Polymer material refractive index :in 10 mins, the fringe spacing became to 40 percent , the refractive index became 2.5 times and keep invariant for Polymer material; in 50 mins, the fringe spacing became to 56 percent ,the refractive index became 1.7 times and kept invariant for ethanol. That’s all, at the time of balance, it will not infect the capability of the Polymer material any longer.

Abstract: Aiming at the difficulty of measuring orientation degree of polymer material online, a soft-sensing approach based on ultrasonic velocity measurement is proposed．Firstly, the ultrasonic velocities of polymer samples are measured using a DSP-based ultrasonic velocity measurement circuit, with the ultrasonic sensor perpendicular to the extrusion direction of polymer material, the orientation degrees of samples are calibrated with infrared spectroscopy, the relationship between the ultrasonic velocities and the orientation degrees are then established based on SVM. With the measurement model and the ultrasonic velocity measured online, the orientation degree of polymer material can then be measured online. Test results in Lab shows that this approach can implement accurate measurement, and the relative error is about 5%.

Abstract: It was investigated that the influences of the peeling behavior of adhesive tapes in peeling tests on IC chip pick-up performance. Needles peel off an IC chip with an adhesive film from the base material in the pick-up process, by sticking out the backside of the base material. In the case that the peeling forces of the adhesive tape decrease as the peeling speeds increase in peeling tests, only two kinds of behaviors were observed in pick-up test; the peeling propagated little and the IC chip was not peeled off under critical needle displacement while the pick-up was completed instantaneously over critical needle displacement. In the case that the peeling forces of the adhesive tape increase as the peeling speeds increase, the pick-up time decreased as the needle displacement increased. As a result, it can be concluded that the needle displacement where the peeling propagates instantaneously is critical for succeeded pick-up if the peeling forces of the adhesive tape decrease as the peeling speeds increase. If the peeling forces of the adhesive tape increase as the peeling speeds increase, the information of peeling speeds at each needle displacement are needed to estimate how long it takes to pick-up a chip.

Abstract: Numerical calculation method is adopted to analyze to the influence of the polymer material on the sensitivity of coated FBG. The calculation results show that, the polymer material with high Young's modulus and high thermal expansion coefficient helps to improve the temperature sensitivity of the coated FBG; and the material with low Young's modulus and low Poisson's ratio helps to improve the pressure sensitivity. The polymer-coated FBG experiment is explored, in which the pressure and temperature sensitivities are enhanced 12-fold and 7-fold respectively.

Abstract: A new kind of passive underwater acoustic sensor based on fiber Bragg grating is reported. The pressure sensitivity of the sensor is enhanced three orders of magnitude being packaged with polymer material, which is a foundation for underwater acoustic detection. An intensity modulation scheme is adopted to realize high-accuracy detection due to the extra-narrow line-width laser. The experimental results show that the sensor’s noise-limited pressure detection resolution is about 61dB (0dB＝1μPa/ Hz ) at 500 Hz, which satisfies the application of underwater target detection.

Abstract: Studying the surface characteristics of polishing pad helps to understand and analyze the chemical mechanical polishing (CMP) mechanism and optimize the microscopic structure of polishing pad. The surface roughness, organizational structure, porosity, depth and diameter of micro-pore, distribution of asperity and profile bearing rate of IC1000/Suba IV polishing pad were studied with the profilometer ZYGO 5022, AFM and SEM. The results of measurement and calculation show that the surface roughness is 6.8μm , the root mean square ( RMS ) roughness is 9.4μm, the surface porosity is 56 % , the micro-pore average diameter is 36μm , the micro-pore average depth is 20μm , the micro-pore average spacing is 43μm , the micro-pore average volume is 550/mm2 and the asperity height obeys Gaussian distribution.

Abstract: The paper proposes that cold insulation property is improved by adding additives and adopting different polymer materials and shows polymer material broad prospects in cold insulation structures. The paper has certain reference value to polymer material performance research.

Abstract: X-ray stress measurement with sin2ψ method is one of useful tools to detect residual stresses in manufactured products. In this study, the residual stresses in the tungsten fiber reinforced polyethylene composite were examined by X-ray stress measurement technique. The transmission diffraction method was employed in residual stress measurement of polyethylene matrix. The X-ray elastic constant of high density polyethylene (HDPE) which formed matrix of the composite was estimated before residual stress measurement. The results of sin2ψ diagram with transmission method show good linearity under the several tensile loading. After that the residual stresses in the composite were investigated for HDPE matrix phase. From the measurement results, the tensile residual stresses existed in fiber longitudinal direction and compressive ones in transverse direction for HDPE matrix.

Abstract: It presented a novel manufacturing method that was derived from traditional hot embossing technology to fabricate actuators on polymer material in this paper. The conventional photolithography technology, electroplating, and hot embossing technology were utilized in this process. The plastic deformation properties of thermoplastic polymers were main concept. The metal layer deposited on the silicon wafer could be embedded into the polymer substrate by hot embossing technology as temperature being above Tg. When the polymer substrate temperature was cooled below the Tg, the polymer is to de-embossing and remove silicon wafer. The metal layer was transferred from silicon wafer to be embedded in the polymer substrate. Owing to the adhesion between the metal layer and polymer material was more than the metal layer and silicon wafer. For instance, the PMMA was employed as the polymer substrate to fabricate the cantilever beam actuator using the novel technology. Finally, the beam was driven by electrostatic force through 25volts of DC power.