SPE Library

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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Conference Proceedings

Cast-In-Place (CIP) for Joining and Repairing Live, PE, Gas Lines - III. Repair of Holes

Robert A. Grimm, Bob Geoghegan, Arthur C. Eberle, May 2002

The cast-in-place (CIP) approach was adapted to a simplified process for repair of holes in polyethylene (PE) pipes. The approach involves clamping an elastomerlined clamshell around the damage and, after the pressurized flow has been stopped, embedding the clamshell in a shell of PE. This work defines:Design aspects of a low-profile steel clamp including examination of several elastomeric gasket materialsDamage types that can be sealed including roughened and damaged surfacesInexpensive and portable methods for strapping the clamp securely around large holes to seal leaking gas under substantial pressureSuitable lengths for the clamp and the PE shell that is molded around it.The overall approach works quite well and clamp designs were found that will seal leaking gas at pressures up to 770 kPa. The clamp is capable of taking flattened pipe and rounding it as it seals holes that are up to 8-cm long in 6-cm diameter SDR-11 gas pipe. Clamp lengths should be no more than 1/3 the length of the cast PE sleeve.

Catastrophic Failure of the No-Slip Condition at the Wall during Torsional Flows and Development of Gross Surface Irregularities during Capillary Flow of Three Polymers

Halil Gevgilili, Dilhan M. Kalyon, May 2002

Wall slip behavior of three polymers was studied using flow visualization in cone-and-plate and parallel plate flows. The straight line marker technique and high speed cinematography were used to investigate the temperature-dependent wall slip behavior of a high density polyethylene, HDPE, a polydimethylsiloxane, PDMS, and an oxetane based thermoplastic elastomer, BAMO/AMMO. Capillary rheometry was also used to obtain data on the flow curves and to study the surface topology of extrudates. The straight line marker technique allowed the precise determination of the critical shear stress values for the onset of the catastrophic failure of the no-slip condition, which were determined to be 0.22 MPa for the HDPE and 0.073 MPa for PDMS, both of which were independent of temperature. In the vicinity of these critical shear stresses the extrudates of HDPE and PDMS exhibited surface distortions during capillary flow. The thermoplastic elastomer, BAMO-AMMO, on the other hand, did not exhibit any catastrophic failure of its no-slip condition and the surfaces of its extrudates remained smooth even at relatively high shear rates during capillary flow.

Cellulose Fiber Reinforced Polypropylene: Compounding and Properties Study

J.E. Dalpiaz, May 2002

The physical properties and processing limitations of polypropylene copolymer compounded with hardwood and softwood cellulose fiber were investigated in this study. The use of maleic anhydride grafted polypropylene as a coupling agent between the cellulose fiber and the polypropylene copolymer was also explored. The addition of the maleic anhydride grafted polypropylene showed improvements to the tensile, flexural, izod impact, and heat deflection temperature properties of the cellulose fiber reinforced blends. The performance properties of the cellulose fiber reinforced materials are also compared to polypropylene blends utilizing more traditional thermoplastic reinforcements: glass fibers, talc, and wollastonite.

Challenges in Winding Flexible Packaging Film

R. Duane Smith, May 2002

Every Flexible Film Producer is faced with the challenge of producing quality rolls of film products. This paper will assist in overcoming the challenges in winding flexible packaging films. It addresses the definition of a quality roll of film and the importance of inwound tension in consistently producing good quality rolls. It then discusses the winding principles used on all winders to control inwound tension or roll hardness. It explains how to determine the proper amount of web tension for various types of films and the principles of nip and gap winding. Then the basic types of center, surface and combination center/surface winders will be compared with the advantages and disadvantages of each. After the discussion of how roll hardness is achieved, methods of measuring roll hardness are presented. Finally, other roll defects to avoid in producing quality rolls of film will be listed and the book Roll and Web Terminology" will be brought to the audience's attention for them to learn more about the causes and cures of common roll and web defects."

Chaotic Mixing as a Means to Develop Nano-Scale Structures in Polymeric Materials

D.A. Zumbrunnen, May 2002

Nanoscale materials are often produced either by breaking down larger structures or by assembling them directly from their smaller constituents. Another approach is to establish processing conditions where initially large component domains intermingle and refine over time to eventually give materials with nanoscale features. In this paper, the potential of chaotic mixing to develop in situ fine-scale structures and promote molecular-scale interactions are described. Due to induced chaotic motions, melt domains stretch and fold recursively. Structure is evolved in lieu of being broken down as occurs typically in common blending. Hierarchical associations among components can arise with relation to some natural materials. Examples of materials are shown that have been produced. Several opportunities are discussed that may allow the manufacture of bulk quantities.

Characterising the Biaxial Properties of Materials Used in Thermoforming and Blow Molding

N. Martin, E.M.A Harkin-Jones, P.J. Martin, May 2002

In most thermoforming or blow molding processes a heated plastic sheet undergoes rapid deformation into the shape of a mold. Typically a wide range of deformation modes may be observed across its surface, ranging from planar through to equi-biaxial. Data from conventional uniaxial tests is often used to simulate this behavior, but it is recognized that neither the speed nor mode of deformation is correct. In this paper the development of a biaxial testing machine is described. Test results for a number of common materials are presented and the results are compared to uniaxial tests.

Characterization of Apparent Viscosity with Respect to a PVC-Wood Fiber Extrusion Process

Timothy M. Bender, May 2002

Wood fiber-thermoplastic compounds were introduced into the marketplace during the mid-1990’s. These compounds are currently being molded or extruded into useful products.As these products grow in complexity, the variability within these compounds must necessarily be reduced in order to maintain or reduce scrap during these secondary processes. But just how much variability these processes can actually tolerate is a non-trivial problem involving design, process and material variables.This paper will discuss the results of a Design of Experiments conducted to determine the maximum apparent viscosity variability that a profile extrusion process is able to tolerate in a PVC-WF compound.

Characterization of Ethylene-Vinyl Chloride-Like Copolymers Synthesized by Ring-Opening Metathesis Polymerization (ROMP)

Catherine H. Stephens, Hongli Yang, Manirul Islam, Stuart J. Rowan, Anne Hiltner, Eric Baer, May 2002

A series of chlorine containing ethylene copolymers with controlled molecular microstructure have been made using ring opening metathesis polymerization (ROMP). In contrast to traditional methods currently used in industry, this synthesis permits the control of the exact chlorine content along the macromolecular chain. In some cases, the placement of chlorine along the polymer backbone is also controlled. The properties of these ethylene vinyl chloride-like copolymers (EVC) are compared to traditionally chlorinated polyethylene (CPE) as well as to ethylene octene (EO) and ethylene styrene (ES), copolymers synthesized by metallocene catalysis.

Characterization of Fluorinated Polycarbonate Thin Films

Anne Cristine Chinellato, Luiz A. Pessan, Mário Bica de Moraes, May 2002

SF6/Ar plasma treatment using an RF discharge was carried out for the surface fluorination of bisfenol-A polycarbonate films. The potential utility of this treatment for improving polycarbonate gas barrier properties was investigated. Treatment was done with variation on time exposure to plasma and SF6 concentration. Fourier transform infrared spectroscopy attenuated total reflection (FTIR-ATR), x-ray photoelectron spectroscopy (XPS), and contact angle measurements were used for surface characterization. It was found that plasma fluorinated surfaces lead to a considerable improvement on polymer gas barrier properties for all treatment conditions studied.

Characterization of Heat Sealing Part on Plastic Films

Tsujii Tetsuya, Kitagawa Kazuo, Machiko Mizoguchi, Daisuke Watanabe, Hiroyuki Hamada, May 2002

Mechanical properties of heat sealed part on plastic films consisting of oriented polypropylene (OPP) and cast polypropylene (CPP) films were investigated and the relationship between crystalline structure and the mechanical properties were discussed. The crystallinity of the heat sealed part affected the mechanical property. Consequently the high total crystallinity of both OPP and CPP gave the high mechanical properties, and also the orientation of the crystalline structure in OPP film was an important factor. The optimum condition for heat sealing was the temperature at which the highest crystallinity was obtained and also the orientation was not released.

Characterization of Metallocene EPDMs Crosslinked by Peroxide and ?-Radiation

J. Nicolás, J.C. Merino, J. Santos, N. Villarreal, J.M. Pastor, May 2002

Two metallocene EPDMs with the same weight fraction of ethylene were crosslinked by dicumyl peroxide and ?-radiation. Several amounts of peroxide were dispersed in a Leistritz corrotating twin-screw extruder at 85ºC, 55 rpm and 2 kg/h of mass flow rate. Besides, different ?-radiation doses were used. The gel content was determined in boiling decahydronaphtalene, and the crosslinking process was monitored by FTIR spectroscopy. The thermal properties were found by DSC and DMA. The mechanical properties, hardness (Shore A), compression set and tensile were also obtained.

Characterization of Molecular Weight Degradation of Polyamides by Gel Permeation Chromatography

Anthony R. Cooper, Gibson B. Pinkerton, May 2002

Polyamides are susceptible to attack by environmental pollutants. The surface layer is degraded and the development of a critical thickness of this layer results in a catastrophic loss of mechanical properties. In this work nylon was exposed to nitrogen oxides and the fracture strength was measured. After a period of no change the fracture strength decreased dramatically. Exposed samples were microtomed and the molecular weight distribution of nylon was determined, as a function of depth from the surface, by Gel Permeation Chromatography (GPC). A critical depth for degradation was established beyond which the specimen exhibited unacceptably low fracture strength.

Characterization of Phase Partitioning of Additives in Rubber Modified Plastics

Patrick B. Smith, Walter C. Buzanowski, Judy J. Gunderson, Duane B. Priddy, Lance Pfenninger, May 2002

The phase partitioning of additives in polymer blends has a large impact on the performance of the blend. Since solubility characteristics and processing of the blends influences partitioning, it is necessary to be able to quantify the level of the additive present in each phase. An NMR method to quantify this partitioning has been developed and is based on the fact that the rubber phase and molecules dissolved therein, can be easily distinguished due to this phase’s enhanced motional characteristics. Examples will be presented for the quantification of phase partitioning within rubber modified styrenic materials.

Characterization of Phenolic Composites Reinforced with Jute/Cotton Hybrid Fabrics

Eliton S. de Medeiros, José A.M. Agnelli, Kuruvilla Joseph, Laura H. de Carvalho, Luiz H.C. Mattoso, May 2002

The mechanical and dynamic-mechanical properties of novolac type phenolic composite reinforced with jute-cotton hybrid woven fabric were investigated as a function of fiber orientation and type. Scanning electron microscopy (SEM) was carried out to investigate the fiber-matrix adhesion. Results showed that the composite properties are strongly influenced by the test direction and yarns characteristics. The highest tensile, flexural and impact strengths and moduli (Young’s, flexural and storage) were found along the jute yarns direction and decreased with increasing test angle. Nevertheless, failure occurred in a catastrophic manner. Along the cotton yarns direction the composite exhibited a controlled failure mode. Jute fiber exhibited a better interaction with the matrix than cotton; the former has a higher irregular surface due to its multicellular nature, which promotes a mechanical adhesion at the interface. The combination of jute/cotton properties in this composite is suitable for lightweight structural applications, this is, jute promotes a higher reinforcing effect while cotton fiber avoid catastrophic failure.

Characterization of Polydimethylsiloxane Deposition on Hair by XPS and Imaging SIMS

Tiejun Wang, Kie Ho, Hsing Yeh, May 2002

The deposition of polydimethylsiloxane (PDMS) on hair for prototype shampoos was studied against competitive products as benchmarks. SIMS reveals uniform coverage of PDMS on hair for both the prototypes and the benchmarks. XPS and SIMS results show that the benchmarks leave substantially higher amount of PDMS on hair while the prototypes deposit 1-2 monolayers. The high PDMS deposition could be related to the consumer perception of smooth feeling, manageability and good rinsability, and could also be related to high conditioner build-up. The results provide insight towards an understanding of structure-performance relationship of hair care products, which helps deliver consumer benefits in a tailored manner.

Chemical Resistance of Elastomers in Harsh Environments

D.M. Bigg, R.M. Hodge, K.J. Heater, May 2002

The performance of a wide range of elastomers exposed to fuel and hydraulic fluid at elevated temperatures was measured. The stability of the elastomers was determined by the degree of mass absorption, volume swell, change in hardness, and change in tensile properties. Other important parameters monitored included changes in glass transition temperature and the quantity of material extracted from the elastomer by the heated test fluids. Performance was measured after 3 and 28 days of immersion in the test fluids at either 107ºC or 135ºC. The classes of materials examined included PP/EPDM thermoplastic elastomers, thermoplastic and thermosetting polyurethane elastomers, nitrile rubbers and hydrogenated nitrile rubbers, epichlorohydrin elastomers, and several formulations of fluoroelastomers.

Chlorine Resistance Testing of UV Exposed Pipe

J. Couch, M. Toro, K. Oliphant, P. Vibien, May 2002

A test methodology to determine the effectiveness of Ultra-Violet Light (UV) stabilization on the oxidative stability of piping materials is examined. Chlorine Resistance (CR) testing is used to determine the impact of accelerated UV exposure on the oxidative resistance of crosslinked polyethylene (PEX) pipe. Following accelerated UV exposure, samples are tested to failure under accelerated test conditions designed to simulate chlorinated potable water end use environments. CR testing in conjunction with UV exposure is shown to be a sensitive method for the evaluation of the effectiveness of UV stabilization on the oxidative stability of PEX pipe. For the particular material examined, it is demonstrated that excellent retention of oxidative stability can be achieved when suitable UV protection is employed.

Closed-Loop Viscosity Control for Injection Molding

A.S. Bakharev, R.G. Speight, P.A. Brincat, May 2002

This paper describes an automated closed-loop control system that compensates for plastic viscosity variations by directly controlling the machine parameters of an injection molding machine. Viscosity is evaluated using a primary injection pressure integral, and compensated for by changing the temperature profile settings of injection molding machine. The shrinkage changes due to the melt temperature changing are compensated for by adjusting the holding pressure. The paper discusses the theoretical basis of the algorithm and presents experimental results on testing the algorithm.

COF Analysis of POP and LLDPE Films Containing Erucamide: Effect of Repetitive Testing

Amol V. Janorkar, Douglas E. Hirt, Jeffrey J. Wooster, May 2002

Erucamide is incorporated into polymer films to reduce their coefficient of friction (COF). Such a reduction in COF is important in packaging lines where the performance of the film in contact with rollers can be governed by the frictional characteristics of the film. This research explores the COF behavior of multilayer films with either POP or LLDPE as the skin layer. Film-on-metal COF testing was performed repetitively with the same piece of film to investigate the extent of COF change with the number of runs. Film-on-film studies were also performed for comparison with the film-on-metal tests. Complementary analysis was conducted with atomic force microscopy (AFM) to investigate whether erucamide was being removed from the film surface or simply being smeared over the surface.

Co-Injection Molding of PVC with Other Thermoplastics: Processing, Properties, and Applications

Mark Parsons, Paul Toyoda, May 2002

Rigid polyvinyl chloride (PVC) was co-injected with glass fiber reinforced PVC (GFR-PVC), polypropylene (PP), acrylonitrile-butadiene-styrene copolymer (ABS), and polycarbonate (PC) using the Mono-sandwich co-injection process. Up to three through-thickness skin-core morphologies were observed along the length of the sample. Near the gate, the core was always a single, continuous layer. In some cases, the core diverged into multiple or discontinuous layers. Further from the gate, flow of the core ceased, leaving a skin-only region. The skin and core layers were more uniformly distributed through the test plaque when injection speed was low. Adhesion between PVC and PP was poor. Skin and core layers delaminated and mechanical properties were poor. PVC adhered well to GFR-PVC, ABS and PC. No layer delamination occurred and mechanical properties were intermediate between those of the skin and core components alone. Dropped dart impact energy was controlled more by the skin layer than the core. In rigid PVC/GFR-PVC co-injected samples, impact energy was 2.5 times greater when GFR-PVC was the core than when GFR-PVC was the skin.