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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Low Shear In-Mould Decoration-Processes for the Manufacture of Three-Dimensional Molded Interconnect Devices (3D-MID)
The aim of Molded Interconnect Devices is to integrate in an injection moulded part with structured plated surfaces electrical and mechanical functions. One of the promising manufacturing methods of 3D-MIDs is the In- Mould Decoration-Process, which uses a plastic-film with a circuit-pattern plated on its surface. Problems which occur sometimes in the conventional In-Mould-Decoration- Process are the damage of the circuit structure or the plastic- film due to high shear stress and pressure during injection. Another problem could be the warpage of the device. Different process-variants which are capable to overcome this difficulty like thermoplastic foam moulding and injection compression moulding were evaluated. Of major concern in the investigation was beside the warpage the adhesion between the plastic-film and the substrate depending on different process-variants of In-Mould Decoration.
Crystallization and Chemi-Crystallization of Recycled Photodegraded Polymers
Injection molded bars have been made from blends containing recycled photodegraded polymers, then subjected to further ultraviolet (UV) exposure. Crystallinity measurements have been made at different depths from the exposed surface using X-ray diffraction and differential scanning calorimetry. Complementary information in the form of molecular mass distributions has been obtained using gel permeation chromatography, and the crystallinity results are interpreted in terms of molecular scission and photo-initiated molecular defects.
The Design, Construction and Operation of Equipment to Investigate the Response of Open, Coloured, uPVC Profiles to Solar Gain
Laminated and dark coloured uPVC profiles, when exposed to sunlight during normal use, may occasionally suffer deformation. To gain a greater understanding of this phenomenon, a number of test rigs were developed to recreate the temperature increase, through the use of infrared heating elements, to simulate varying intensities of solar radiation.
Considerations for Relating Artificial Laboratory and Natural Outdoor Weathering Durability Testing
This paper reviews considerations for linking laboratory and outdoor reference exposure weathering durability data. Laboratory considerations include designing experiments and developing predictive functions using xenon arc devices. Reference exposure considerations include monitoring meteorological and irradiance exposure variables in Florida and Arizona. Exposure data is compared for polycarbonate.
Control of Directional Electrical Conductivities in Carbon Black-Thermoplastic Exrtrusions Produced by Chaotic Advection
Whereas prior related work involved batch devices, an industrially relevant continuous flow chaotic mixing process has been used in this study to form structured distributions of carbon black in extruded films. Methods were also applicable to other extrusion profiles. Carbon black masterbatch was formed into numerous filamentary striations that yielded conducting states at low overall compositions. A range of electrical properties were selectable via process parameter specification. Differences in directional conductivities along the width and length of the film were controllably obtained. The progressive formation of structure was related to electrical properties and process conditions.
Nondestructive Characterization of Orientation in Thick Cast and Drawn Polyaniline Films
Polyaniline (PANI) films 20 to 50 microns thick cast from N, N’-dimethylpropylene urea (DMPU) solution and stretched to different draw ratios were examined. The thickness of these visibly opaque PANI films posed severe limitations on available structural characterization tools. NIR wave guide coupling, X-ray diffraction and FTIR infrared dichroism methods were used. Two new infrared transition moment angles for weakly absorbing bands were determined for the PANI molecule. This allowed the Hermans’ orientation function for the thick PANI films to be determined nondestructively.
Improving Gel Compatibility of Polyolefinic Polymers for Loose Buffer Tubes in Fiber Optic Cables
Loose buffer tube designs in fiber optic cables (FOC) generally include hydrocarbon oil based gels to fill the tubes for mechanical and moisture protection. Conventional olefinic polymers typically show reduced performance in compatibility testing due to a high level of hydrocarbon oil permeability. In particular, impact-modified polypropylene (IMPP) requires specially formulated and, therefore, more expensive gels to retain modulus and tensile properties after oil exposure. Described herein is the gel compatibility performance of a developmental product made with INSPIRE* Performance Polymers that provide a substantially improved balance of impact toughness, high modulus and gel compatibility for the optic buffer tube application versus the conventional polyolefin materials currently used. Also outlined are preliminary results of ongoing material studies targeting further improvement in gel compatibility performance.
Investigation of Packaging Properties as a Function of Filler Microstructure
Fillers are used in the molding compounds to minimize the stress of electronic packaging by reducing the coefficient of thermal expansion (CTE) mismatch between the silicon die and the molding compounds.This study concentrates on the effect of filler particle spatial distribution. Quantitative measures of the particle distribution were experimental determined, including area fraction, size and interparticle distance (IPD). A 2×3×3 ANOVA test was also conducted to assess the statistical significance of these variations of measures. The difference of filler volume fraction at different positions within one chip can be as big as 10%, and cause a CTE difference of about 4 ppm/°C.
Conductive Polymer Blends for Injection-Molded Bipolar Plates
This work aims at developing lightweight low-cost bipolar plates for use in proton exchange membranes (PEM) fuel cells. New material formulations using polypropylene (PP) and polyphenylene sulfide (PPS) as matrices and carbon black, graphite, and carbon fibers as conductive additives were developed. These formulations have properties suitable for bipolar plate manufacturing, such as good chemical resistance, sufficient fluidity, and high electrical and thermal conductivity. Two prototype plates of different design were successfully fabricated by over-molding aluminum plates or simply by injecting the high conductive materials into the final shape.
Experimental Study for Underfill of Flip-Chip Packages
Today, most flip chips are encapsulated by dispensing the encapsulant along the periphery of the sides of chip. As the dispensing process fills the space between chip and substrate by capillary force, the flow is very slow and could result in filling incomplete or voids. Therefore, as chip size increases, the filling problems become more serious. For this reason, it is critical for flip-chip technology to speed up the encapsulation process and avoid defects.This paper studies the theories of the material properties, contact angle and surface tension,etc. Moreover, some transparent molds with different number/size of bumps and different layout patterns are used to study molding phenomena. The experimental results are further used to verify the use of CAE tools.
Failure of Plastic Plumbing Products
Failures of plastic components are being seen more often in industrial, household and commercial settings. Many of these failures involve the transport of water and cause significant damage when they occur. These failures can be caused by improper material specification, bad design, over loading or incorrect molding conditions. Issues such as chemical resistance, environmental deterioration, geometric sensitivity, temperature dependence and aging are at times overlooked.
Reliability of Joining Plastic Parts
Critical items in designs of plastic products are joints. The paper will deal with a number of design aspects about designing reliable plastic products. It will combine the results from our research in the field of stress concentrations, orientation and weld lines around holes, embrittlement of polymers, adhesion and environmental stress corrosion. A number of failures in practice will be presented.
Performance Characteristics of a Styrene-Isobutylene Block Copolymer Produced by Living Cationic Polymerization Technology
A completely saturated styrene-isobutylene based thermoplastics elastomer has been produced at the industrial scale for the first time. Triblock (SIBS) of Mw range 65,000 to 100,000 have been produced. Due to the saturated main chain of polyisobutylene, these products are superior in heat rersistance, gas barrier properties and damping properties.
Nano-Composites via Solid-State Modification for Toughening in Semi-Crystalline Polymers
Chemical modification of isotactic polypropylene in solid-state using various monomers –initiator systems has been investigated. In particular porous iPP is modified in solid-state by grafting silanes or acrylates using free radical initiators. Silica like nano-particles were formed in-situ via sol-gel reaction in pre-modified solid porous iPP. These silica-clusters were of nano-scale varying from 30-200 nm in size, and retained the size even after processing (extrusion). Grafting and silica formation via sol-gel is characterized using FT-IR and 29Si Solid-state NMR. Morphological characterization (using TEM and SEM) showed uniform distribution and dispersion of silica particles in matrix before and after processing. DSC and WAXD results revealed that silanes, when grafted on iPP, nucleate and induce ?-phase. Improvement in toughness and effect on thermal properties of polymer were also investigated and mechanism of toughness enhancement is proposed.
Polypropylene/Clay Nanocomposites: Characterization and Interpretation of Structure - Property Relationships
Polypropylene (PP) nanocomposites were obtained by melt compounding of PP and organoclays in the presence of maleic anhydride grafted polyolefin compatibilizer. The effects of compatibilizer type and content and the mixing sequence on the morphology and properties of the PP/clay nanocomposites were investigated. PP nanocomposites exhibit enhanced mechanical properties compared with neat PP and they also are thermally more stable. Rheological properties are sensitive to the composite structure and thus are a valuable indication of the degree of exfoliation.
Novel Nanostructured Polymer Blends with Enhanced Benefits
Molecular-level blending of reactive polymers can provide an alternative and economical route to producing new polymers with special structures and improved properties. In this paper, we report results of our experimental efforts to generate compatibilized polypropylene (PP)/polyamide 6 (PA6) blend via in situ polymerization and in situ compatibilization of polypropylene, ? -caprolactam and maleic anhydride grafted PP that is impossible to achieve using conventional polymer blending methods reported in the literature. The intrinsic molecular-level blending and compatibilization of the preparation method allowed formation of nanostructured PP/PA6 blends with interesting stable interpenetrating or co-continuous morphologies that can be controlled during processing. Thermal and morphological measurements revealed that the compatibilization effect of the blend is significantly better than that obtained from conventional reactive blending of premade polymers. With proper control of the thermodynamics, interfacial tension (through use of chemically modified functional polymer) and deformation rates, particle coalescence could be suppressed, making it possible to generate the polymer blends with very small (< 100 nm) polydispersities. These blends could find applications in a number of high-end uses such as optics, drug delivery, tissue engineering, and permeable membranes for separation phenomena.
PBT and PET Ionomer Based Clay Nanocomposites
Poly(butylene terephthalate), poly(ethylene terephthalate) and their respective ionomers were utilized as matrices in the formation of organically-modified montmorillonite clay nanocomposites. These materials were prepared using melt extrusion with a variety of clay concentrations. The small angle x-ray scattering and transmission electron microscopy data revealed that low levels of sulfonation in the polyester ionomers resulted in exfoliated clay nanocomposites. Moreover, the orientation of the clay platelets within injection molded dogbones was found to increase with increasing sulfonation level of the ionomers. The affect of clay dispersion on the thermal and mechanical properties of the nanocomposites was investigated. The enhancements in mechanical properties produced by the ionic functionality were attributed to an increase in the number of interactions between the clay platelets and the matrix via electrostatic interactions involving the sodium sulfonate groups. In addition, a tentative model of how the negatively charged, sulfonate groups along the polymer chains interact with the montmorillonite clay platelets to improve the exfoliation of the clay platelets was provided.
Performance Enhancing Crosslinked SBR Masterbatches for Thermoplastic Elastomers
Masterbatches of crosslinked solution-polymerized styrene-butadiene random elastomers (XL-SBR) and polypropylene (PP) were prepared and used for enhancing the oil resistance, compression stress relaxation performance, lowering gloss, and compression set of styrene-ethylene/butylene-styrene (SEBS)-based thermoplastic elastomer (TPE) compounds. Enhanced performance was achieved when SBR partly or substantially replaced the SEBS component. Modification of SEBS compounds in the Shore A range of 45-85 with the crosslinked SBR is discussed.
New Soft EPDM Rubber Concentrate for Toll Compounding to Produce High Flow Thermoplastic Vulcanizates (TPVs) for Injection Molding Applications
New soft EPDM rubber concentrate can be used to produce thermoplastic vulcanizates (TPVs) with improved flow properties by toll compounding processes for injection molding applications. By adding various amounts of polyolefin plastics such as polypropylene homo polymer or copolymers, TPVs with different durometers and properties can be made easily using compounding equipment such as twin screw extruders or other mixing equipment with sufficient mixing capability.
New Thermoplastic Vulcanizates (TPVs) with Improved Processibility for Injection Molding Applications
A new line of thermoplastic vulcanizates (TPVs) has been introduced by DSM Thermoplastic Elastomers for injection molding applications where UV resistance is critical. This new line of products, consisting of several grades with hardness ranging from 50 to 85 shore A in black color, shows superior flow characteristics and balanced properties meeting existing automotive material specifications. In this paper, we will discuss some of the features associated with this new line of products.
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