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.
Many products and assembled systems of different products require the use of threaded plastic to threaded metal connection to provide the mechanical integrity required for the service application. While there are design guidelines and industry acceptable standard specifications related to the design of the different thread profiles used in the connection of plastic to plastic or connection of metal to metal threaded components, there is very limited information available for designing a plastic to metal threaded connection. Generally, designing a mechanical connection between a plastic threaded component and a metal threaded component is discouraged. However, in some applications this cannot be avoided and as such the lack of understanding related to plastic to metal threaded connection leads to product failures when such connections are made or designed improperly into products.
This paper reports two case studies of product failures where plastic to metal threaded connections contributed to product failure that caused either personal injury or personal property loss. A failure analysis investigation was conducted to evaluate the thread design in two products in which plastic to metal threaded connections were involved in the product failure. In the first case-study, the thread connection was found to be insufficient in the mechanical strength and in the second case study the root cause of failure was determined to be excessive tightening of the female threaded plastic component onto a male threaded metal component.
Polyvinylchloride (PVC) is the most commonly used thermoplastic resin for electrical cable coatings. PVC that hardens after polymerization is not suitable for insulating and protecting wires and cables. The necessary mechanical, thermal, and electrical levels can only be reached with the addition of softeners, stabilizers, and fillers. Composition of the good and the bad PVC samples were analyzed using FTIR spectroscopy and TG analysis.
It was found that ditridecyl phthalate was used as a softener in both samples. Magnesium oxide was used as a filler in one sample. The higher amount of water that present in the sample at room temperature and evolves during the first stage of PVC decomposition might be responsible for the low heat resistance of one sample.
The objective of this study was to characterize popular commercial bed-in-a-box mattress and visco topper foams, which are the benchmark bedding products in the market. These products were advertised as gel infused foams that offer superior thermal conductivity and support. Multiple techniques were utilized to identify the composition of the foams. In summary, the commercial “green” and “gray” bedding polyurethane (PU) foams were similar in composition, and they were made of glycerin-initiated PO/EO based polyols. It also showed the incorporation of styrene-acrylonitrile (SAN) in the polymer backbone. The isocyanate part was consistent with an aromatic isocyanate identified as methylene diphenyl diisocyanate (MDI). In addition, the blue gel polymers that were infused to these foams were polyurethane based material. Furthermore, the black particle in the “gray” foam that was advertised as heating wicking material was graphite-based additive.
Polyvinyl Chloride (PVC) foaming was studied as a function of high molecular weight acrylic processing aids. It was demonstrated that an ultra-high molecular weight processing aid is 25-30% more efficient than relatively lower, but still high, molecular weight acrylic processing aids. The higher Mw processing aid provided similar foaming performance at lower loading levels. Foaming reduced the density of PVC compounds to 0.32-0.34 g/cc. More than 1000% expansion was achieved in the melt extrusion process using a chemical blowing agent. Fusion characteristics were also studied. Fusion times for initial fusion peaks were in the range of 42-44 seconds while the fusion times of the second fusion peaks were in the range of 74-94 seconds. The higher molecular weight processing aid maintained fusion characteristics of PVC compounds, warranting no significant changes in extrusion process.
Thin samples of a pipe-grade polyethylene with a bimodal molecular weight distribution were exposed to 5ppm 70C chlorinated water for up to 3000 hours. The samples were characterized by tensile tests, size-exclusion chromatography, infrared spectroscopy, and differential scanning calorimetry. Throughout exposure, the molecular weight data showed evidence of degradation: weight-average molecular weight was reduced, and a shift in the molecular weight distribution from a bimodal to a unimodal distribution (decreased dispersity). After 2250 hours of exposure, brittle behavior was observed, in which the average elongation at break was 12%. At this level of degradation, the weight-average molecular weight was 9 % of its undegraded value, and the crystallinity had increased from 70% to 85%. Average tensile strength was reduced from 31.8 to 16.6 MPa. The data imply that the presence of short-chain branching may inhibit chemicrystallization and subsequently delay the onset of brittle behavior.
Cellulose nanocrystal (CNC) suspensions were compounded into blends of poly(lactic acid)(PLA) and poly(vinyl acetate)(PVAc) using a novel wet compounding approach in which drying and compounding werecarried out simultaneously. The resulting CNC/PLA composites were compared with those produced using a more traditional method of freeze-drying CNC suspensions followed bymelt-blending into PLA. CNCs in wet compounded composites appeared to be well-dispersed in the PLA/PVAc blends, and films extruded from these compounds exhibited high transparency compared with melt-blended composites. Gel permeation chromatography indicated that molecular weight degradation due to wet compounding was comparable to that from melt blending. The formulation, including surfactant modified CNCsand PVAc processing aids, played a significant role in the dispersion and properties of the nanocomposites. The elimination of a stand-alone drying stepfor cellulose nanomaterials can potentially overcome some of the challenges associatedwith producing thermoplastic cellulose nanocomposites and help advance commercialization of these materials.
Failure analysis and reverse engineering can greatly expedite product development. Infrared and Raman spectroscopy is the among the most powerful tools for this application because each molecule has a unique infrared and Raman signature. Infrared and Raman microscopy was successfully used to identify foreign particles on elastomers and to depth profile multilayer polymer film. Details of the measurement techniques are discussed.
A reduced order kinetics model is proposed for the corrosion of polyethylene in bleach solution. Hypochlorous acid (ClOH) is considered as the oxidizing agent which is formed from the hydrolysis of bleach. The model simulates the diffusion of ClOH into the non-polar polymer matrix followed by its dissociation into radicals. The reaction between the radicals and the polymer is phenomenologically modeled using an ordinary differential equation. The model is suitable for coupling with mechanical models for life-time analyses of polymers members under mechanical loading and exposure to corrosion. The model captures the effect of the chain oxidation process which causes the accelerated aging of the polymer.
Hydroxyl-terminated polybutadiene (HTPB)-based rubber composite is usually used for solid propellant binder. In order to investigate the long-term material properties in the storage environment, it is recommended to set up the conditions refer to MIL-STD-810G. After aged for 100, 200, 300 hours with different temperature and humidity conditions, the key properties, i.e. tensile test, Fourier transform infrared spectroscopy (FTIR), and surface morphologies were examined. Also, by using these experimental data, diffusion model using finite element method suggested. This study will be useful for the life evaluation of HTPB-based composites considering diffusion.
Kim McLoughlin Senior Research Engineer, Global Materials Science Braskem
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Kim drives technology programs at Braskem to develop advanced polyolefins with improved recyclability and sustainability. As Principal Investigator on a REMADE-funded collaboration, Kim leads a diverse industry-academic team that is developing a process to recycle elastomers as secondary feedstock. Kim has a PhD in Chemical Engineering from Cornell. She is an inventor on more than 25 patents and applications for novel polyolefin technologies. Kim is on the Board of Directors of SPE’s Thermoplastic Materials & Foams Division, where she has served as Education Chair and Councilor.
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Gamini has a BS and PhD from Purdue University in Materials Engineering and Sustainability. He joined Penn State as a Post Doctorate Scholar in 2020 prior to his professorship appointment. He works closely with PA plastics manufacturers to implement sustainability programs in their plants.
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Tom Giovannetti holds a Degree in Mechanical Engineering from The University of Tulsa and for the last 26 years has worked for Chevron Phillips Chemical Company. Tom started his plastics career by designing various injection molded products for the chemical industry including explosion proof plugs and receptacles, panel boards and detonation arrestors for 24 inch pipelines. Tom also holds a patent for design of a polyphenylene sulfide sleeve in a nylon coolant cross-over of an air intake manifold and is a Certified Plastic Technologist through the Society of Plastic Engineers. Tom serves on the Oklahoma Section Board as Councilor, is also the past president of the local Oklahoma SPE Section, and as well serves on the SPE Injection Molding Division board.
Joseph Lawrence, Ph.D. Senior Director and Research Professor University of Toledo
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Dr. Joseph Lawrence is a Research Professor and Senior Director of the Polymer Institute and the Center for Materials and Sensor Characterization at the University of Toledo. He is a Chemical Engineer by training and after working in the process industry, he has been engaged in polymers and composites research for 18+ years. In the Polymer Institute he leads research on renewably sourced polymers, plastics recycling, and additive manufacturing. He is also the lead investigator of the Polyesters and Barrier Materials Research Consortium funded by industry. Dr. Lawrence has advised 20 graduate students, mentored 8 staff scientists and several undergraduate students. He is a peer reviewer in several journals, has authored 30+ peer-reviewed publications and serves on the board of the Injection Molding Division of SPE.
Matt Hammernik Northeast Account Manager Hasco America
A Resin Supplier’s Perspective on Partnerships for the Circular Economy
About the Speaker
Matt Hammernik serves as Hasco America’s Northeast Area Account Manager covering the states Michigan, Ohio, Indiana, and Kentucky. He started with Hasco America at the beginning of March 2022. Matt started in the Injection Mold Industry roughly 10 years ago as an estimator quoting injection mold base steel, components and machining. He advanced into outside sales and has been serving molders, mold builders and mold makers for about 7 years.
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How to reference articles from the SPE Library:
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, ISBN: 123-0-1234567-8-9, pp. 000-000.
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.
