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.
In this work we report on the quantification of concentration profiles across the polystyrene-polyvinyl methyl ether interface through ATR-Attenuated total reflection technique. Different narrow molecular weight distributions and different temperatures above and below the glass transition temperature of polystyrene were tested both in the one phase and two-phase regions. The effects of temperature and molecular weight on the diffusion mechanism are discussed in terms of the phase behavior.
A single specimen J-integral approach is developed to determine the fracture toughness of thin polyethylene blown films. The test is used to determine the amount of energy required to initiate crack growth as well as the energy required to propagate the crack. This paper presents preliminary findings using the single specimen J-integral approach on LLDPE blown films. A comparison between J, Elmendorf, and Dart is provided.
The crack growth resistance in chlorinated water has been measured for two polyacetal resins of different molecular weights. The crack growth rates were measured using single edge notched tensile specimens under constant stress at elevated temperatures. The crack resistance measured in hot water containing free chlorine were found to provide a reasonable explanation for the observed poor field performance of these resins in hot water plumbing applications.
Fluorescence anisotropy area scans of sheet and film specimens have been carried out using a fiber optic sensor that contains polarizing optical elements. Measurements on polyethylene terephthalate food packaging, which contains the fluorescent dye benzoxazolyl stilbene, are presented. In one case, a sheet cut from the side of a blow molded bottle displayed variation in biaxial orientation as a function of distance from the neck of the bottle. In another case, a thin film of shrink wrap material showed uniform biaxial orientation over the scanned area.
Mixing of miscible additives into polymeric matrices is being investigated using the model blend SAN/PMMA. The normalized sample variance, as measured by FT-IR, is used to quantify the extent of mixing. The graph of normalized sample variance as a function of sample size reveals that there are at least two characteristic size scales present in short-time mixing samples. Theoretical calculations support this conclusion.
The objectives of the study are to: 1)Determine the relationship between cavity pressure and tool failure; 2)Evaluate the feasibility and effectiveness of cavity pressure transfer from first to second stage for stereolithography (SLA) produced tooling; and 3)Evaluate the effectiveness of computer simulation in determining the startup conditions for the AIM* injection molding process.
External pressure was applied to extruded LLDPE films with an average thickness of 70 microns at 35°C and 50°C for prescribed periods of time. The final surface concentration of the slip agent (erucamide) was then compared to the initial concentration. Three applied pressures were used and diffusion profiles were determined using FTIR-ATR spectroscopy.
Experiments were performed to determine the performance of three floating ring mixing devices. The mixers studied were 1) a Twente mixing ring, 2) a Barr sleeve mixer, and 3) a Barr ring mixer. Performance was measured using extrudate sampling, extruder performance, and extrusion solidification experiments.
Melt viscosity is calculated by observing contaminant flow in a low density polyethylene melt stream. The melt stream is radiated by visible light and images of flowing particles are captured and processed. Particle flow rates are measured across the stream, and a velocity profile is then determined. Viscosity is calculated from this profile.
Sharkskin melt fracture (SSMF) of, especially, LLDPE has been studied for several decades because of its economic importance and scientific interest. SSMF occurs on extrusion of some--but not all--polymer melts; examples include LLDPE, PDMS and polybutadiene (PBD). PBD exhibits remarkably similar flow and SSMF behavior to LLDPE, but is easier to work with. Evidence for the origin of SSMF inside the die was sought, but not found, leaving the exit as the probable source of SSMF for this resin.
Many an industrial polymer product reveals, once its quality diverts from set standards, either a change in color or an increase in fluorescence. After their accelerated ageing, various products are scanned on special flatbed scanners and their filed images are then color coded to determine with high accuracy their color composition, fluorescence intensity and the extent of their discoloration during processing.
One of the most common environmental exposures that nylon undergoes when used for automotive applications is that of salt splash, which commonly occurs during winter driving. This study looks at the effect of various salts (NaCl, KCl, CaCl2) on the mechanical and thermal properties of nylon when exposed to one and four molar aqueous salt solutions. Also, the partition of the salt/water solutions was studied, as well as the preferential absorption of one salt over another.
Because the heating rates in hot-tool and vibration welding are very different, and the higher weld pressures used in vibration welding induce more squeeze flow, the weld zones in these two processes see very different flows and cooling rates, resulting in different morphologies. The weld morphologies of bisphenol-A polycarbonate and poly(butylene terephthalate) for these two processes are discussed in relation to these differences.
The use of CAE1 as a powerful tool to analyze injection mold quality has given encouraging results. CAE is used to deal with mold troubleshooting and to solve problems concerning Filling Time, Injection Pressure, Gate Position and Dimensions, Warpage, Coolant Efficiency, etc. This paper focuses some of these parameters to its weightiness for Mold Technologies Division. Therefore CAE is a powerful tool to assure quality, price and time delivery.
Effect of specimen thickness on flexural properties of particulate filled and continuous fiber reinforced composites was investigated by 3-point bending test according to ISO10477. Results showed that flexural strengths and moduli decreased with the increase in specimen thickness. Loss of flexural properties in thicker specimens compared to those in thinner specimens was higher in fiber reinforced composite than in particulate filled composite.
The rheological properties of ethylene/styrene interpolymer (ESI) systems ranging in styrene content up to 80 wt% (50 mol%) and in melt index from 0.5 - 10 are discussed. Dynamic mechanical spectroscopy, melt strength, and pressure-volume-temperature data will be presented along with corresponding relationships between these data and applications of ESI.
Direct compounding has long since been eastablished in sheet-, profile- and pipe-extrusion, where the high cost-advantages of single-stage article production are appreciated . Compared to extrusion applications, direct compounding of injection molded articles is comparitively unknown territory. The IMC-process (Injection Molding Compounding) enables filled or reinforced plastics to be direct-compounded immediately before injection molding. This offers two advantages to the molder: his material costs are reduced and he gains in flexibility.
There are many choices and options available for motors and drives for extruders and other machinery used in extrusion lines. This paper provides an in-depth explanation of DC, AC Vector, Servo, Brushless DC, and other common drive and motor technologies. It covers how they work, their major differences, their pros and cons, and some guidelines in how best to apply them. This knowledge should help plastics engineers in the selection of extrusion equipment.
The positive displacement characteristics of a twin-screw extruder are often attributed to the intermesh of the two screws. Our objective was to measure velocity distributions in the nip and the translational regions of a co-rotating twin-screw extruder. The variation of axial and tangential velocity with screw rotation changed significantly from the translational to the nip region. Much higher axial velocity values were measured in the nip when compared with those measured in the translational region.
Instrumented drop weight impact test was used to study the effect of thermal degradation on the impact properties of PVC compounds. The impact resistance of the aged compounds related well with their weight loss and hence thermal degradation. Each compound showed a specific weight loss percentage that correlates with a 50% loss in its impact properties (failure point) irrespective of the aging temperature. The results were also used to estimate a thermal index (TI) of each compound in a rapid and reliable way.
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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
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