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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Zhiyong Xia, Hung-Jue Sue, Zhigang Wang, Benjamin S. Hsiao, May 2002
The determination of the crystalline lamellar thickness in semicrystalline polymers is a tricky issue. In this paper, three methods have been employed to analyze the lamellar thickness in semicrystalline polymers. The three methods are small-angle X-ray scattering correlation function method, Fast Fourier Transformation and transmission electron microscopy. Based on this study, the larger value of the two correlation length values should be assigned as the lamellar thickness.
Material recycling requirement gradually opens the automotive body sealing market to thermoplastic elastomers (TPE), which is primarily dominated by EPDM thermosetting elastomers. Due to special material behaviors of elastomers, careful attentions should be taken when analyzing the body seal performance using material testing data, especially for TPE materials. This paper will address some of the issues by analyzing body seal products using TPE materials. The general guidelines for body seal analysis and result evaluation will also be discussed.
A.S. Bakharev, R.G. Speight, A.R. Thomas, May 2002
This paper presents a new algorithm for the automatic setting of the rotational speed, back pressure and barrel temperature profiles in a reciprocating screw injection molding machine. The algorithm is based on a computer simulation of polymer plastication. It achieves maximal throughput and good quality of melting and mixing within the limits provided by the injection molding machine.
L. Mulvaney-Johnson, P.D. Coates, R.G. Speight, May 2002
A process initialisation and setup system for the gas assisted injection moulding process is developed. The initialisation routine uses settings taken from the machine operator or machine controller to formulate the starting point for the process settings. A setup routine is required that automatically changes process settings on the machine controller to provide an acceptable product. Process variables are monitored along with feedback from the operator on the condition of the product. The process initialization routine is outlined here.
It is widely known that single screw extruders are poor mixers and improving mixing in single-screw extruders is a challenging task, especially under low shear conditions. In this paper, a methodology based on chaotic mixing sections, spread over almost half of the screw length, is described to improve mixing characteristics of immiscible and miscible polymer systems under low shear conditions.
A developmental Thermotropic Liquid Crystalline Polymer (TLCP) made by Eastman with tradename LN001 was used for barrier property studies. The permeability of methanol and toluene through a membrane of the TLCP was studied using a two-part cell and a Gas Chromatograph to monitor the flux. The membranes of the TLCP and LDPE (as control) were made by compression molding. Both solvents had higher permeability through LDPE than TLCP and that of Toluene was higher than Methanol.
This paper will briefly discuss the history of barrier screws and then discuss the design features and resulting performance in single screw extruders. Barrier screw operation in smooth feed and grooved feed machines will be discussed. Comparisons of barrier screw performance to conventional screws will show where the benefits lie and a few examples of where there is less advantage or even disadvantages with barrier screws.
A novel reactor-made polypropylene-g-poly(methyl methacrylate) (PP-g-PMMA) was used as a component for forming binary blends with bisphenol-a-polycarbonate (PC) and ternary blends with PC and polypropylene (PP). Results showed that the morphology and physical properties of these blends were strongly composition dependent. The compatibility window was determined based on the physical properties and the morphology. The binary blend of PP-g-PMMA/PC shows excellent chemical and stress cracking resitance as compared to PC.
A novel feature of chaotic mixing, that of formation of self-similar mixing structures, is utilized in this study to produce an array of mixing microstructures, such as nested layers, elongated fibrils, droplets and their combinations in the blending of two immiscible polymers, polypropylene (PP) and polyamide-6 (PA6). The effects of initial length scale of segregation, viscosity ratio of the phases, mean shear rate, and the degree of chaotic mixing are studied.
The brittle-to-ductile transition temperatures (TBDs) for miscible copolyester/polycarbonate blends are studied using single edge notched bend specimens. The pure copolyester TBD and pure polycarbonate TBD are lower than the TBDs of copolyester/polycarbonate blends. This decrease in toughness is evaluated by examining the yield strength and craze strength as a function of temperature and blend composition.
Material selection, part design, mold design, and processing must all receive proper attention in order to prevent product failure. This paper will profile case studies of failed products where each one of these fundamentals was neglected. The studies will illustrate the analytical processes used to assign a root cause to each of the problems and will suggest corrections that can prevent costly failures from recurring.
This paper describes a method for casting a non-leaking sleeve of polyethylene (PE) around the butted ends of PE pipes while the joint is leaking air at pressures up to 388 kPa. The step of casting the sleeve was the critical unknown step in a repair sequence that might be used to repair leaking natural gas pipes. Equipment, parameters, heating profiles, and the effects of mud and water on joint strengths are described.
Russell Edwards, Liyong Diao, Charles L. Thomas, Mike Groleau, May 2002
An ultrasonic transducer was installed on the back of the cavity plate on an injection mold such that the sound vibrations would strike the surface of the mold cavity and reflect back to the transducer. Exciting the transducer in continuous wave mode, a resonant system is produced. When the mold fills with polymer this system is damped and the resonance is changed. By monitoring these changes it is possible to monitor conditions inside the cavity during processing.
Gregory A. Campbell, Sirisha Bomma, Samuel St. John, Shaji Chempath, May 2002
Chaotic mixing in the extruder channel, obtained by the periodic motion of top and bottom walls of the channel is considered here. An analytical solution for the flow field in the extruder is used in all the simulations presented here. Using the increased degrees of freedom of the free-helix single-screw extruder, chaotic mixing can be obtained. Experimental evidence for the increased mixing of a dye in an extruder under chaotic flow field is presented.
Polystyrene foam(PS foam) both without and with 1% Benzoyl peroxide coated were found to be exponentially degraded within 6 months under the open-air and artificial weathering exposure. The reaction mechanism of this foam was identified as chain scission. The peroxide was effectively used as photo accelerator. The experimental data and also the statistical hypothesizes analysis using t-test with the 95% degree of confidence suggested that the data obtained from the open-air and the ones from artificial weathering exposure were analogous.
The two main methods of cross-linking commercial hot water piping used in industry today are the electron beam method and the chemical method using a silane reactant. Piping cross-linked using both methods will be compared in order to determine which method produces better mechanical properties.
This paper presents the results of a study that was conducted to show whether process control software works as well or better than the part weight or cavity pressure methods in determining gate freeze.The study was done with three different molds using two materials for each mold. The molds utilized all had cavity pressure transducers close to the gate. The materials used were nylon and ABS, in order to contrast semi-crystalline and amorphous behaviors.
The compounding of long fibre reinforced composites based on flax and a polypropylene matrix has been implemented by a co-rotating, close-intermeshing twin-screw extruder. Extensive experiments have been carried out to optimise the fibre/matrix adhesion and the screw concept. Only short fibre structures could be achieved by the use of conventional screw elements, like kneading blocks or turbine mixing elements. Applying newly developed special screw elements long fibre structures as well as an optimum fibre dispersion could be reached.
Resistance to velocity, rV , should be used as a criterion in the prediction of gas direction in gas assisted injection molding. In addition, melt resin velocity is also used in the prediction. Comparison of the velocity of fluid is especially important for more complex situations. These methods predict the gas flow direction from the knowledge of process variables such as resin flow length, cross section area of cavity, melt temperature, and short shot.
This lecture provides an overview of a group effort on NIR electroluminescence along with visible and IR electrochromism. Significant advances continue to be made in developing visible light emitting PLED’s and electrochromic polymers with visible color responses. Less effort has been directed to longer wavelengths.
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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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