SPE Library
The SPE Library contains thousands of papers, presentations, journal briefs and recorded webinars from the best minds in the Plastics Industry. Spanning almost two decades, this collection of published research and development work in polymer science and plastics technology is a wealth of knowledge and information for anyone involved in plastics.
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Conference Proceedings
Processing and Mechanical Properties of Continuous Fiber Reinforced Thermoplastics
Asami Nakai, Tsutomu Narita, Eisuke Fukui, Iwao Komiya, Hiroyuki Hamada, May 2004
In this study, multi-axial warp knitted thermoplastic composites were fabricated by our-developed Micro-braiding technique. Cross-sectional observation, tensile test and 3 point bending test were performed. The composite with good impregnation state was obtained under appropriate molding conditions, consequently high mechanical properties were achieved. The multi-axial warp knitted fabric composite without unimpregnated region had the equivalent mechanical properties with unidirectional composite laminates. Moreover, new concept of continuative fabrication method was proposed.
Measurement System Analysis for Viscosity Measurement of Highly Filled Biofiber Composites
Shankar Godavarti, May 2004
A comprehensive measurement system analysis (MSA) on measurement of apparent viscosity using the slit die method was conducted. Nine materials and three operators with three repeats were used. P/T (precision to tolerance) and P/P (precision to process) ratios were estimated from gage R&R analysis. Repeatability was found to be greater than reproducibility. Slip analysis on the wood fiber composites indicated that these composites essentially flow by slip mechanism. Six Sigma methodologies with rigorous method development resulted in establishing control materials and implementing SPC in a manufacturing plant.
Injection Molded Biocomposites from Natural Fibers and Modified Polyamide
M. Misra, A.K. Mohanty, P. Tummala, L.T. Drzal, May 2004
This paper focuses on the development of a new technology and process in order to manufacture natural fiber reinforced engineering thermoplastics like nylon 6. Natural fibers are not suitable reinforcements when high temperature melting (above 200°C) engineering thermoplastics is used as matrix materials because natural fibers start to degrade thermally at above 200°C. Small quantities of inorganic salts like lithium chloride were added to the nylon 6 during melt extrusion processing to depress its melting temperature. The final composites are injection molded into test specimen at the reduced processing temperatures of nylon 6. The molded plastics and composites are tested for mechanical and thermal properties. Natural fiber reinforced nylon 6 composites show improved tensile and flexural properties. The morphology of the fracture surfaces is observed using Environmental Scanning Electron Microscopy.
Processing/Structure/Property Relationships for Artificial Wood Made from Stretched PP/Wood-Fiber Composites
Y.S. Kim, G. Guo, K.H. Wang, C.B. Park, F.W. Maine, May 2004
This paper presents the processing/structure/property relationships for artificial wood made from stretched PP/wood-fiber (WF) composites that have required strength and density. The die drawing of PP/WF composites causes a unidirectional orientation of the polymer molecules and enhances the mechanical properties significantly along the stretched direction. The drawing of the composites also lowers the density of artificial wood by generating voids at the WF and polymer matrix interface. The critical processing and materials parameters are identified. The effects of these parameters on the structure and the properties are also investigated.
Effect of Processing Conditions on the Physico-Mechanical Properties of Cellulose Fiber Reinforced Poly (Lactic Acid)
M.S. Huda, A.K. Mohanty, M. Misra, L.T. Drzal, E. Schut, May 2004
Green composites were made from poly (lactic acid) (PLA) and cellulose fibers by extrusion followed by injection molding processing and their physico-mechanical properties were evaluated. The properties of PLA reinforced with varying amounts of wood pulp-based cellulose materials were studied. These composites possess superior thermal and mechanical properties based on the strong interaction between the PLA matrix and the cellulose fibers. It was found that the wood pulp-based cellulose fiber could be a good reinforcement candidate for the high performance biodegradable polymer composites.
Biobased Composites Manufactured through a Reactive Extrusion of Maleated Wood Particles
K. Carlborn, L.M. Matuana, May 2004
Biocomposites such as particleboard and medium density fiberboard are currently made with formaldehyde-containing adhesives. Since the government is continuously developing and implementing very stringent regulations to eliminate formaldehyde emissions into the environment, alternative approaches must be developed to replace these adhesives. This study examined the concept of using a reactive extrusion process as a means of developing a new, formaldehyde-free binding system for wood composite products. The surfaces of wood particles were modified by grafting maleated polyethylene through a continuous reactive extrusion process. Chemical changes resulting from this treatment were followed by studying the FTIR and XPS spectra. The modified wood particles were compression-molded into panels, which were tested for bending properties. Both FTIR and XPS data revealed that the chemical reactions have taken place between the hydroxyl groups of wood particles and maleated polyethylene. The modulus of rupture (MOR) results showed that the composite panels compared favorably with current standard requirements for particleboard.
Coupling Efficiency of Maleated Polyethylene Copolymers in Wood Fiber-High Density Polyethylene Composites
John Z. Lu, Qinglin Wu, Ioan I. Negulescu, May 2004
Coupling efficiency of several maleated polyethylene (MAPE) copolymers was investigated in this study. Interfacial bonding strength, flexural modulus, and other mechanical properties of wood fiber-high density polyethylene (HDPE) composites were related to coupling agent type, molecular weight, acid number, and concentration. Acid number and molecular weight were two important indexes for interfacial adhesion. Acid number had negative influence on interfacial bonding strength at high concentration, whereas molecular weight had positive effects. Backbone structure of coupling agents also affected interfacial bonding strength. MAPEs with linear low-density polyethylene (LLDPE) backbone were better than those with HDPE and low-density polyethylene (LDPE) structure. Compared with untreated composites, modified composites with 50% of wood fiber were improved in interfacial bonding strength by 140% on maximum and flexural modulus by 29%. According to experimental results, coupling agent 100D, 226 D, and C16 were the best coupling agents. Therefore, coupling agents with larger molecular weight, moderate acid number, and low concentration were preferred to improve the interfacial bonding of the resultant composites.
Mechanical Properties of Carbonized Bamboo Fiber Reinforced Biodegradable Polymer Composite
H. Matsui, K. Kitagawa, T. Semba, H. Okumura, U.S. Ishiaku, H. Hamada, May 2004
The mechanical properties of biodegradable polymer composite with carbonized bamboo fibers were evaluated. Poly (butylene succinate) (PBS) was used as the biodegradable plastic matrix while the condition of carbonization was varied. By increasing fiber content, tensile modulus was confirmed to increase. In particular, the tensile modulus of composite filled with semi-carbonized bamboo displayed higher values than the uncarbonized bamboo fibers composite. The values of tensile strength decreased according to the increase of fiber content; however, the carbonized bamboo fiber composites experienced less decrease than the uncarbonized ones. The surface resistivity of carbonized bamboo fiber composites was lower than that of bamboo fibers and also decreased with the increase in fiber content in each case.
Development of Thermoplastic Electrolytes and their Ionic Conductivity
Tithinum Puatrakul, Soondeuk Jeung, Kyonsuku Min, May 2004
The ionic conductivity of polyethylene oxide film complexed with copper acrylic acid salt (PEO-Cu(AA)2) as well as copper and copper chloride were studied. The effects of the interaction between PEO and salts on their conductivities are discussed with the help of thermal analysis and vibration spectroscopy. Bulk conductivity values were evaluated from the alternating current measurement by constructing impedance plots. PEO-Cu and PEO-Cu(AA)2 complexes exhibited the typical ionic conductive behavior of polymer electrolytes. The ionic conductivity of PEO-Cu(AA)2 complex at room temperature yielded the magnitude of conductivity at 10-6 Seimen/cm.
Electrical Properties of Carbon Nanofiber-Modified Thermotropic Liquid Crystalline Polymers
Sungho Lee, Myung-Soo Kim, Amod A. Ogale, May 2004
Vapor-grown carbon nanofibers (CNFs) were incorporated into a thermotropic liquid crystalline polymer (TLCP, Vectran V400P) to investigate the electrical and mechanical properties of the composite. The percolation threshold was observed in composite films at 5 wt% CNF. With increasing CNF content (up to 5 wt%), the longitudinal tensile strength decreased, whereas the transverse strength increased. Thus, with increasing CNFs, the composite films became not only more electrically conducting but also displayed more balanced longitudibal/transverse properties. The morphological features of CNF-modified TLCP were analyzed by X-ray diffraction. Results suggest that the CNFs lead to the disruption of the TLCP orientation, and may help produce TLCP-based films that have balanced in-plane properties.
Application of Radiation Cross-Linking for the Improvement of the Short-Time Thermo-Mechanical Properties of 3D-MID's
Zaneta Brocka, Gottfried W. Ehrenstein, May 2004
Materials with compounded cross-linking additives, e.g. PA6, PA66 and PBT, were developed to improve the heat resistance of engineering thermoplastics during high short-time temperature-loads. Cross-linking of plastics is a process, with which the individual plastic molecules are chemically bonded together. This process is released through, e.g. electron beam irradiation. The temperature-dependent irreversible mobility of the molecules decreases through cross-linking. Therefore, the softening range is shifted to higher temperatures depending on the degree of cross-linking. This behaviour is considerably interesting for the development of MID-assembles, which will be processed in continuative processes of the electronic production, e.g. soldering. The following paper offers an overview of the potentials of iradiation cross-linked PA for MID-applications.
A Novel CNTs/Polymer/PE Composite with High Electromagnetic Shielding
H-Z. Cheng, W-S. Jou, P-T. Lin, C-C. Huang, E-C. Chen, May 2004
A sandwich structure composite employing polyethylene and multi-walled carbon nanotubes/polymer, which is synthesized by in-situ polymerization on well aligned carbon nanotubes, is demonstrated with high electromagnetic shielding effectness. The shielding effectness of composites related with the orientation of carbon nanotubes embedded in the polyethylene was studied systematically. The shielding effectness of composites with parallel with the normal of polyethylene matrix were measured to be higher than those with carbon nanotubes perpendicularly to the composite surface or randomly oriented with frequency ranging from 0.3 GHz to 3.0 GHz.
Distribution of a Minor Solid Constituent in a Transfer Molded Leadframe Microcircuit Package
Yue Huang, Sheng Zhan, David Bigio, Michael Pecht, May 2004
This study investigates the spatial distribution of a minor particulate constituent in a transfer molded leadframe microcircuit package. The package has been polished at three levels parallel to its top surface. Levels 1 and 2 are above the die and leadframe while level 3 is just below the top surface of the die and leadframe. The distributions of area fraction and size of the particulate were analyzed for each level using micro-photography. Comparisons were made at different levels as well as different positions within each level. Both size and spatial distributions of the particulate material are evidently non-uniform, and its relations with gate, die and leadframe are interpreted. ANOVA tests were conducted to assess the statistical significance of the variations.
Three-Dimensional CAE of Wire-Sweep in Microchip Encapsulation
Wen-Hsien Yang, David C. Hsu, Venny Yang, Rong-Yeu Chang, Francis Su, Sheng-Jye Huang, May 2004
Wire Sweep is a common molding problem encountered in microchip encapsulation. The resin melt flow will exert drag force on wires and hence causes deformation of wires. In this paper, an integrated CAE of wire sweep is proposed to help engineer to evaluate and optimize the encapsulation process. The resin flow is calculated by a true 3D thermal flow solver based on a highly flexible prismatic element generation technique. Thanks to the efficiency of the proposed methodology in terms of CPU time and memory requirement, the industrial packages with complex geometry and high pin count can be analyzed with minimum model simplification. Furthermore, a user-friendly integrated environment is also developed to link the flow analysis with structure analysis to provide the total solution for wire sweep assessment. The developed approach proved from numerical experiments to be a cost-effective method for true 3D simulation of wire sweep in microchip encapsulation
Three-Dimensional Dynamic Simulation of Paddle Shift during Semiconductor-Chip Encapsulation
Sejin Han, Franco Costa, Shishir Ray, Scott Willmorth, May 2004
In this paper, the movement of the paddle during the semiconductor-chip encapsulation process is simulated dynamically. The non-uniform pressure distribution across the paddle will cause the paddle to shift during filling. The movement of the paddle will in turn cause a change in cavity thickness, and thus will affect the flow. This interaction between paddle shift and flow has been simulated. A three-dimensional finite-element method is used for the flow analysis. The simulation results are evaluated using an example case. The effects of mold temperature and filling time have also been examined.
Molding Analysis for Underfill of Flip-Chip Packages
Wen-Ren Jong, Shia Chung Chen, Cheng Chang Lai, Tsung Hsiang Kuo, Hung Wen Liu, Shrwai Ho, Wen-Yang Lo, May 2004
Nowadays, underfill of flip chip is often driven by capillary force to dispense the space between chip and substrate. The flow is very slow and could result in incomplete dispensing or voids. Therefore, as the chip size increases, the dispensing problems become more serious. For this reason, it is critical for flip-chip technology to speed up the encapsulation process and avoid possible defects.This paper setup an experiment to study the influences of bump design, such as gap height, bump pitch and bumped patterns, on the underfill of flip-chip package. These studies could be used to build up the knowledge of underfill process.
The Analysis on the Fatigue Life of Flip Chip Package under Cyclic Thermo-Mechanical Loading
Wen-Ren Jong, Chien-Chia Chiu, Hsin-Chun Tsai, Shia-Chung Chen, May 2004
This study focuses on the reliability of flip chip package under the loading of cyclic temperature. This study shows thorough modeling and analysis of using ANSYS to simulate the thermal conduction and the mechanical behavior of flip chip package. The results reveal that the deflection is caused by the difference of material properties of the components, as such, the maximum equivalent plastic strain of solder bumps always happens at the farthest place from the symmetrical surface of models where the fatigue destruction occurs most easily. Further, temperature cycle test (TCT) was employed to study issues of reliability. The fatigue life was calculated by fatigue-stress and fatigue-strain method respectively in different cycles, material properties, and processes.
Structural Analysis of DC-DC Converters
Wen-Ren Jong, Shu-Hui Peng, Tsung- Hsiang Kuo, Steven Hu, Shr-Wai Ho, May 2004
The compact DC-DC converts consist of one aluminum substrate and two FR-4 substrates which hold electronic components, and molding epoxy. Due to its structural complexity, the device could be easily failed during the thermal cyclic test.This paper presents the complete CAE modeling and integrated analysis of DC-DC converters which can be used to design a better product. A detail 3D model of converters is constructed to understand the behavior of all important components under the thermal cyclic test. The results show the weakest solder-joint spot which can be verified with experimental failure. Some geometrical parameters are also studied to show their importance.
Synthesis and Properties of Polymer Blend Nanocomposites. Part II. Thermoplastic Olefin (TPO)
Keun Yong Lee, Lloyd A. Goettler, May 2004
Nanocomposites with organically treated montmorillonite derived from layered silicates in various PP/EPDM blends were prepared by direct melt intercalation in an internal mixer. In these nanocomposites, the nanoclay reinforcement is constrained to lie selectively either in the continuous matrix or in the dispersed phase or both phases of a thermoplastic olefin. The morphology as well as mechanical properties of the nanocomposite blends are strongly affected by the selective reinforcement of each phase. Morphology characterization by x-ray diffraction (XRD) and transmission electron microscopy (TEM) provide the basis for understanding the observed structure-property relationships in this class of materials.
Rheological Characterization of Polystyrene-Clay Nanocomposites as they Relate to the Degree of Dispersion
Jin Zhao, Rich Fibiger, Rich Fibiger, Nicole Roberman, Lizhi Liu, Eddy Garcia-Meitin, Victor Juarez, Danny King, May 2004
Polymer nanocomposites with as little as 2-vol. percent of layered silicate can dramatically improve tensile modulus, strength, and heat distortion temperature without significant loss of impact strength. Such improvements will have major impact in the material industry and technology. Because viscoelastic measurements are highly sensitive to the nanoscale and mesoscale structure of polymeric materials, when combined with X-ray Scattering, electron microscopy, thermal analysis, and mechanical property measurements, they will provide fundamental understanding of the state and mechanism of exfoliation of layered silicate in polymer matrix. In addition, understanding rheological properties of polymer nanocomposites is crucial for application development and understanding polymer processability.The degree of intercalation, exfoliation, and dispersion has been traditionally characterized by XRD and TEM. While both of them are very effective tools, both are limited by only probing a small volume of the sample and are too costly for routine characterization of nanocomposites. Melt rheology can quantify via a global average on the degree of intercalation/exfoliation/dispersion across whole nanocomposite test specimens usually around 2 grams of samples. It will be less ambiguous than other techniques (e.g. TEM) in quantifying exfoliation/dispersion. In addition, it will be easier to perform than TEM and XRD thereby opening up the possibilities of performing routine studies to better understand the influence of material options and processing conditions for improving nanocomposite exfoliation/dispersion. In this report, the effects of clay dispersion/exfoliation on the viscoelastic properties of polymer/clay nanocomposites are investigated using dynamic mechanical measurements, dynamic shear measurements, X-ray diffraction (XRD), and transmission electron microscopy (TEM). Polystyrene/clay hybrid materials with different degree of dispersion/exfoliation were prepared by solve
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