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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Polymer melts under micro injection molding process experience high shear rates and high thermal gradients, resulting in some unique morphology features. This paper examined the morphology of Pebax 7233 SA01 under designed experimental conditions. With measurement by cavity pressure and temperature (PT) sensors, shear rates and thermal gradients were quantitatively evaluated and related to morphology evolution. Unique spherulites were formed beside the skin layers, having a much larger size than its adjacent larger while the central region had no visible spherulite structure. Their formation, and the related thermomechanical history, were examined. Macro mechanical properties and local mechanical properties of micro molded samples and micro features were evaluated by tensile testing and nano-indenation. The relationship between process, morphology and properties were evaluated and correlated by statistical analysis.
Longhao Yan, Aldo Crugnola, Robert Whitehouse, May 2013
In this thesis, sisal fibers were pretreated by alkaline and acetylation. Observed by the scanning electron microscope, the acetylation surface modification resulted in the best interfacial adhesion between fibers and polymer matrix. The pretreatment washed away the wax and impurities on the fibers surfaces and roughened the surfaces. Two fiber lengths of 3 mm and 10 mm were pretreated by alkaline, but the composites of them showed similar tensile properties. The sisal fibers and polymer matrix materials were mixed by wire coating and batch mixing (with a weight portion of 1:9). Batch mixing was found to offer a more complete surface contact between two phases. Prepared by compression molding, the composites of the acetylation pretreated fibers showed superior Young’s modulus than the composites of alkaline pretreated fibers, untreated fibers, or polymer matrix. The tensile strength of the composites was generally lower than polymer matrix. Moreover, both polymer matrix and composites exhibited similar glass transition temperatures. The composites from alkaline pretreated and ground fibers showed the highest storage modulus below the glass transition temperatures, and the storage modulus of the matrix polymer was lower than the one of composites above the glass transition temperatures.
Ultra High Molecular Weight Polyethylene (UHMWPE) infused with vitamin E, utilized in the manufacture of implantable medical devices, will be characterized for the safety and improved wear rate of the material for use in this application. The following experiments will analyze the chemical and mechanical properties of E-CIMA, a compression molded, irradiated, and mechanically annealed material to a vitamin-E infused UHMWPE that has not been mechanically annealed. This will be done through the use of Tensile, Izod, DSC, and FTIR tests. ASTM standard procedures will be used in the characterization of the materials. We anticipate that removing the step of mechanical annealing, does not have an adverse effect on the mechanical and chemical properties of the material, and still shows an enhancement from standard use non-modified UHMWPE.
A major design consideration and benchmark for a high quality injection molding hot runner system is color change performance. The focus of this project was to evaluate the effect of temperature uniformity on color change performance and frozen layer formation. Trials were conducted using three different hot-sprues representative of typical configurations. The thermal profile of each sprue was mapped at steady state conditions prior to processing. Sprue pulls were then performed to study the efficiency of each color change and results were compared with data obtained from mold filling simulations. It was determined that temperature uniformity greatly altered a system’s color change performance. Cool regions in the sprue formed frozen layers of the original material that would remelt over subsequent cycles negatively impacting the color change performance.
Roll-to-roll (R2R) lithography is a continuous manufacturing process used to create patterns on a polymer substrate. Thermally curing of R2R embossed features is time consuming, and is commonly replaced with faster UV or chemical curing. A technique of induction heating the lithography stamp in a R2R process has been conceived for heating, forming and cooling along the perimeter of the roll. The patterned polymer surface needs no additional curing steps, which increases efficiency of the R2R lithography process. The results of initial investigation prove the feasibility of said conceptual process, and initial experiments confirm heating of the lithography roll by induction heating.
Thermoforming is an important converting technique. Predicting how well a material will perform during thermoforming is difficult without a trial run. The thermoforming index (TFI) was used as a measure of a material’s performance in thermoforming. The TFI test measures a material’s viscous and elastic properties under thermoforming conditions and quantifies how well the material will perform based on those properties. In this study, the thermoformabilities of liquid crystal polymer (LCP) materials were observed using the TFI. Dynamic frequency sweeps were used to estimate the optimum forming temperature. The test was repeated on LCPs with two different levels of filler. Polypropylene (PP) homopolymer, polystyrene (PS) and high density polyethylene (HDPE) were also tested as controls. The relative TFI values found for each control material correlate with their known forming behavior. The filled LCP materials had lower TFI values, which would suggest poor performance. However, the TFI values for filled LCP do not portray completely the observed behavior, as these materials have shown sufficient thermoformability.
Toxicity of some halogenated flame retardants (FR) has resulted in restriction of their use in plastic materials. Therefore, there is significant interest for development of non-halogenated FR with comparable performance. Here, we report a new type of FR additives based on combination of metal oxides and polyphenols. This FR additive is expected to exhibit a combination of char formation behavior and radical scavenging action. Synthesis and thermal characterization of this new class of FR material will be presented.
Flame Retardants (FR) are often compounded into plastics to ensure fire safety. However, some types of halogenated FR additives are environmentally persistent and toxic to humans. Here we report the development of an alternative FR additive based on polyphenol-titania complex that exhibits a combination of radical scavenging and char forming properties. The thermal stability and heat release capacity of blends of this complex with polypropylene are compared to those containing conventional halogenated FR.
Polyamides are widely used in variety of electrical applications because of their good melt flow, chemical resistance, impact, and electrical properties. For applications requiring a glass-filled polyamide composition, with a high degree of flame retardancy, flame retardant additives must be added to the composition. Metal dialkylphosphinates are the preferred flame retardants for polyamides, but they are expensive and must be used in relatively high concentrations. We have discovered that in glass-filled polyamide compositions, desirable flammability, flow, heat and mechanical properties, can be achieved with reduced loadings of Exolit® organic phosphinates, by including specific poly(phenylene ether) masterbatches in these polyamide compositions.
The concept of sustainability is often stated in a number of ways but four core principles appear throughout: Protect the environment, promote human health, conserve resources, and assure social and economic well-being to the global population. PVC resin has intrinsic properties that allow finished products to meet all four of these objectives. PVC resin and products compare favorably to other materials in life cycle assessments when reviewing key impacts of resource and energy conservation, and greenhouse gas emissions. Sustainability assessments at the business level are excellent tools to promote these principles and track performance. This paper was prepared for the Society of Plastics Engineers Annual Technical Conference (SPE ANTEC) Vinyl Session, April 22, 2013 in Cincinnati, Ohio.
From end of screw return melt residence through injection to ejection of a molded part to screw return end time is the thermal dynamic molding process cycle. A micro-bead melt sensor indicates the imposed strains of temperature and radial force strain as melt density “K” electro-motive force (emf) readout. A nozzle melt density sensor profiled consecutive molding cycles of melt fill to final peak pack. The melt pack interruption by screw return time to final mold cure will be presented.
In the field of thermal shielding for aerospace applications Cf/SiC composites are raising great interest, provided that they are protected from oxidation by suitable coatings. Conversely, ultra high temperature ceramics, and in particular HfB2, are among the best oxidation resistant materials known. A coating made of a HfB2/SiC composite (20% weight SiC) was tested as an oxidation protection on a Cf/SiC composite.
Pharmaceutical melt extrusion has attracted much attention recently due to broad applications such as bioavailability enhancement, controlled release and taste masking. This article summarizes the characterization methods utilized in the field of pharmaceutical extrusion, and focuses on three applications: characterization of solid dispersion, process analytical technology (PAT) and solubility measurement of drugs in polymeric materials
A comparison between individual spherulites growth rates and circumferential nodular growth rates for isotactic polypropylene crystallized from the melt was conducted by means of polarized optical microscopy. The obtained results show that both spherulites and nodules grow linearly with approximately similar growth rates at high crystallization temperatures, while individual spherulites grow a little faster at lower crystallization temperatures.
Exposure of the carbon fibre composites (CFC) NB31 and NS31 by multiple plasma pulses has been performed at the plasma guns MK-200UG and QSPA. Numerical simulation for the same CFCs under ITER type I ELM typical heat load has been carried out using the code PEGASUS-3D. Comparative analysis of the numerical and experimental results allowed understanding the erosion mechanism of CFC based on the simulation results. A modification of CFC structure has been proposed in order to decrease the armour erosion rate.
Yusuf Oni, Theresa Hermel-Davidock, Srini Sridharan, May 2012
This paper presents the results of an experimental study into the mechanisms of fiber tear as it affects blister packaging for medical devices. Physical and chemical characterizations of different paper/film combinations were carried out. Results show hat fiber tear is largely due to the extent of mechanical interlocking of the paper fibers with the adjoining film. Suggesting hat the chemistry on each paper surface can further assist in influencing the extent of mechanical interlock observed.
Polymeric interlayers like Polyvinyl Butyral (PVB) - films between glass sheets make it safe in case of breakage. But, in the case of recycling, the adhesive interlayer makes the laminated glass difficult to cut. Fortunately, the mostly used PVB is a polymer which can easily been solved in different agents. Using this possibility the present investigations show that recovered PVB can be used in laminated safety glass again.
The viscoelastic behavior of physically crosslinked copolymer hydrogels synthesized from N, N-dimethylacrylamide (DMA) and 2-(N-ethylperfluorooctane sulfonamido) ethyl acrylate (FOSA) is discussed. These gels have a core-shell nanodomains structure that is responsible for the crosslinks. High modulus (80 – 130 kPa), elongation (1000 – 1600 %), a tensile strength ~500 kPa and toughness (4 – 6 MPa) were achieved. The exceptional properties are due to the reversible nature of the physical crosslinks and their ability to dissipate energy.
A rapid extrusion process has been developed to make high flow polyesters in a melt reaction with a primary alkyl amine. In addition to much higher flow the modified resins show slightly faster crystallization but with reduced impact. This process has also been used to make high flow fiber glass filled PBT. It provides a low cost, fast option to make a wide variety of high flow resins from one staring material.
Black specks and color streaks in injection molded parts can reduce the yield and profitability of an injection molding process. This paper presents some of the common root causes for black specks and color streaks, and the technical solutions to remove them. Three case studies are presented.
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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
Available: www.4spe.org.
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.
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