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.
The introduction of servo-driven ultrasonic technology, with Dukane’s iQ Series Servo system, provides a new level of control to an already fast and flexible welding method. This breakthrough has allowed greater consistency than ever before possible with ultrasonic welding, one of the most widely used processes for bonding polymers. In the medical industry, there is a great need for reliable weld results in production. Some of the most forward thinking manufacturers of medical parts have already benefitted from servo-driven ultrasonic equipment. One of these manufacturers, Value Plastics, A Nordson Company, a leader in the design and manufacture of plastic tube fittings and connectors, began working with Dukane's servo-driven ultrasonic welder in the second quarter of 2010. Already, they have used the servo welder in full production projects and are completing the research and development phase for additional jobs. Every one of these projects has shown improved weld consistency over the previously employed pneumatic welders.
The damage of glass fibers at various conditions was investigated by varying viscosity, screw speed, screw configuration and glass fiber length and diameter. Increasing screw speed, melt matrix viscosity and glass fiber concentration were found to increase the extent of fiber breakage. Based on our experimental data and Euler buckling theory the composite modular kinetic model to describe glass fiber damage was developed. Regions of major and minor fiber breakage in co-rotating twin screw extruder were established. The simulation program based on experimental data and kinetic constants was developed. Comparisons were made between simulated results and experimental data.
The dependency of PLA extrusion foaming on three different fillers (nanoclay, nanosilica, and talc) and their impact on crystallization has been investigated. PLA with nanofillers showed smaller cells due to more nucleation sites, whereas talc showed bigger cells. Nucleated crystals can be a secondary reason for the increase of cell density for all cases. However, increasing the filler content decreased the cell size in the case of talc due to the higher crystallization rate, which creates bigger nucleation sites with bigger cells
There are growing interests in the area of flame retardant (FR) thermoplastic materials, especially in thin wall applications. Consistency in flame rating measurement is critical in FR resin development and commercialization. However, flame performances are difficult to assess due to a multiplicity of factors that influence the material behavior, such as, molding conditions, operator training and orientation of specimen during testing. In this study we have investigated the role of ? mold/barrel temperatures ? injection speed ? switch point ? holding pressure on flame properties of a Lexan* grade of polycarbonate so that we can eliminate/ reduce the effects of molding parameters during flame testing This was done by first investigating the effect of post molding residual stress on flame properties. It was observed that the such properties of are influenced by the post- molding residual stress profile built-in the bars and that such profile is in-turn influenced by the processing conditions.
Two recent efforts on mechanical characterization of ductile polymeric thin films are presented. One is on fracture toughness determination of polyolefin thin films and the other is on scratch deformation study of laminated films for food packaging applications. Characterization of fracture toughness of ductile polymer thin films is nontrivial. It requires extreme care in sample preparation to avoid premature film damage, in fixture design to minimize out of plane film rotation, and in meaningful analysis to establish structure-property relationship. The essential work of fracture approach has been chosen for quantifying fracture toughness of ductile polyolefin films. Issues related to sample preparation, data generation and interpretation are discussed. Possible correlation between the fracture toughness and other industrial practices is also made. In the case of scratch test, it is found that the scratch performance correlates well with the field performance of the films. The usefulness of the scratch test for evaluating film structural integrity, adhesive strength between film layers, and laminate structural design optimization is discussed.
This paper investigates the foaming behaviour of crosslinked Ethyl-vinyl acetate (EVA) using a chemical blowing agent (CBA). In this study, foaming experiments were conducted using the chemically crosslinked polyolefin foamed BUN process, with the help of a compression molding machine. It was found that an optimum degree of crosslinking was needed to produce high quality EVA foams with high expansion ratios. A mountain-shape curve can be used to describe the relationship between the expansion ratio of the EVA foams and the crosslinking content. Furthermore, with more blowing agent used in the foaming process, the value of the optimum crosslinking content at the expansion ratio peak increases.
We have investigated epoxy/MWCNT nanocomposites and propose that the primary role of the nanoparticles is to reduce stress concentrations at internal defect sites. This leads to improvement in ductility and tensile strength without affecting modulus. The shielding of internal defects may also allow synergistic interaction with secondary particles. This behavior is reported to promote improved fracture toughness in the presence of pre-formed thermoplastic particles, and substantially enhanced modulus and strength when coupled with exfoliated nanoplatelets.
This paper investigated the thermal and dynamic mechanical properties of solid and microcellular injection molded PLA/ PHBV blends of different weight ratios. The properties were characterized by DSC and DMA. The results showed that when the content of PHBV exceeded 45% it could significantly affect the crystallinity of the PHBV and improve the G' for both solid and microcellular components. It was also found the Tg of the PLA phase decreased with increasing PHBV content.
Using solid-state shear pulverization, we have identified the potential to functionalize polypropylene by taking advantage of near ambient temperature reactions. Polypropylene was pulverized in the presence of benzoyl peroxide; under these temperature conditions the decomposition of benzoyl peroxide results in the formation of benzoyloxy radicals that react with the polypropylene chain, introducing ester functional groups onto the chain. Fourier transform infrared spectroscopy indicates that such functionality cannot be obtained using conventional high temperature processing methods.
Two types of polystyrene were injection molded into macroscale parts with microscale features. UV photolithography was utilized to create microchannels on the surface of silicon wafers. Higher mold temperatures facilitated filling of the microfeatures. In addition, an undercut microchannel feature promoted pillar elongation. HIPS exhibited greater heights at identical mold temperature conditions. Pillars with heights of 15 µm were molded with an aspect ratio of 9.3. Polymer surfaces could provide control of biological cell activity
Polymer nanocomposites offer a potential solution to improve, while maintaining, multiple, incompatible properties, such as mechanical and optical performance. In order to demonstrate significant property enhancements, a well-controlled dispersion of a nano-scale filler into a polymer matrix is required. Melt processing represents the most economical and flexible route to producing thermoplastic nanocomposites. This paper describes a set of melt compounding experiments to help establish the kinetic and thermodynamic factors that govern the dispersion of layered silicates in ionomers. The results show that the stress imparted during the melt blending influences dispersion. However, the thermodynamic compatibility between the filler surface, organic modifier and matrix polymer plays a dominant role in the exfoliation process.
In this work, an algebraic-differential equations (EAD) system is applied to estimate parameters using both isothermal and non- isothermal data. Temperature dependence of the specific heat is considered inside the EAD as an algebraic restriction. The estimation procedure is based on the use of a mass and energy balance in DSC furnace. The approach found all kinetic parameters by using deterministic and heuristic algorithms. The results show that the use of an energy balance is a good methodology to estimate cure kinetic parameters of both isothermal and non-isothermal experiments.
There are two processes to polymerize polycarbonate in the petrochemical industry: One is interfacial polymerization(interfacial PC) and the other is melt polymerization(melt PC). Recently, the latter is mostly used in that it is eco-friendly process. The most difference of product produced by two systems is the content of specific end-group. It is detected to a little bit value in interfacial polymerization, while it generally has more content in melt polymerization. It is supposed that the more content of the end-group is, the bigger change of the property induce as surrounding environment. In order to analyze an effect of the end-group, polycarbonate substituted to other end-group was made from melt PC using a suitable end-capping agent. And then, several properties were examined like melt index, viscosity and color. As the result, the end-capped PC showed less change of the properties than general melt PC, and it is similar to interfacial PC. It was verified that the properties of melt PC is adversely affected by the specific end-group.
Current trends in renewable resin systems for composite applications will be presented in this talk. Our recent efforts on synthesis of lignin-based bio-thermoplastics show significant promise. Various methods of establishing chemical synthetic routes for producing lignin-based thermoplastics that can increase the value of lignin by-products will be discussed. Compatibilization of blends of lignin with different polymeric matrices results good thermoplastic for certain lignin loadings. These routes would provide a low-cost alternative, recyclable resins for future composite applications.
This work highlights three decades of polyester resin development for the extrusion blow molding (EBM) process. The optimal formulation for a clear EBM material must fulfill three main requirements: process efficiently on existing equipment, produce bottles with robust drop impact performance, and have an acceptable recyclability story. Balancing these criteria in a single formulation is challenging, since obtaining compatibility in the PET recycle stream inherently causes drawbacks to processing and bottle performance. Nevertheless, significant innovation has enabled Eastman to provide the market with a comprehensive portfolio of copolyester technology, suitable for a variety of needs.
Dibenzoates plasticizers are well established and are used in PVC applications. Chemically these plasticizers are non-phthalates and dibenzoates function well as high solvating type plasticizers. In the past, new benzoates, dibenzoate blends and grades were developed to keep pace with formulators’ needs. A new generation dibenzoate triblend platform has been developed to offer formulators an improved high solvator to complement general purpose plasticizer performance. A basic plastisol evaluation protocol was utilized to help determine how to formulate with these new blends. In addition to the basic data developed, examples of performance in starting plastisols will be shown.
The screw extruder is one of the mostly used equipment for polymer processing and its conveying mechanism is based on the shear flow. This leads to the materials experiencing a long thermo-mechanical history. Vane extruder is an innovative equipment which totally alters the shear conveying mechanism of screw extruder. The solid compacting and conveying section, the establishment of pressure section and the melting section simultaneously occur in the vane extruder which is different from the screw extruder. This results in the short thermo-mechanical history in the vane extruder. And the crushing of solid-bed and the elongational flow are generated in the vane extruder. Therefore, it does not decrease the plasticating and mixing effects even though it has shorter thermo-mechanical history than the screw extruder. The plasticating and mixing effects are found better in the vane extruder compared to the screw extruder through the experimental investigations.
By using a pull-out test the mechanical bonding at the interface fique fiber-Low Density Polyethylene- Aluminum (LDPE- Al) matrix was measured. Experimental results of the shear stress at the interface point out that a critical length of 21 mm optimally transfers the stresses from the matrix to the fiber. In addition, a volume of 50% fique fiber showed better mechanical strength when compared to volumes of 10 and 30%. Optimization of the critical length and volume ratio (fique fiber/matrix) allowed the manufacturing of boards using a hot plate machine.
Polymer manufacturing utilizes metal parts which are reclaimed for reuse. Traditional reclamation methods utilize solvents and other chemicals which have high energy demand and involve expensive disposal methods. The DEECOM® technology, solvent-free relatively low temperature reclamation technology, is based on pressure swing techniques designed to physically disrupt and remove polymer from parts. The process mechanism results in filter reclamation procedures that have high degree of sustainability and provide opportunity to recycle the removed polymer.
The dispersion of nanoscale reinforcements in polymer matrices remains a significant challenge in achieving desired properties in nanocomposite materials. Polyhedral oligomeric silsesquioxane (POSS) nanostructured chemicals, consisting of an inorganic cage structure with an organic corona, provide a unique opportunity to control nanoscale dispersion by tuning the organic substituents to allow interaction with specific substrates. The structure can also be tailored to provide preferential surface segregation in a polymer melt to achieve desired modification of surface properties. The estimation of POSS solubility in polymer matrices through calculated solubility parameters and molecular dynamic simulations will be discussed in relation to experimental results. The dispersion of POSS and POSS-modified nanoparticles in selected systems will be reviewed.
Any article that is cited in another manuscript or other work is required to use the correct reference style. Below is an example of the reference style for SPE articles:
Brown, H. L. and Jones, D. H. 2016, May.
"Insert title of paper here in quotes,"
ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
Society of Plastics Engineers
Note: if there are more than three authors you may use the first author's name and et al. EG Brown, H. L. et al.
If you need help with citations, visit www.citationmachine.net