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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Process of Transition in Croatian Plastics and Rubber Industry
Business world is exposed to accelerated, revolutionary changes, driven by results of scientific research and fast technical progress, globalization process, the growing use of the Internet and the development of ebusiness. Companies are trying to adjust to these changes and at the same time they are fighting against rising costs and competition. The situation is much worse for companies from the so-called countries in transition, like Croatia. They went through a very painful process of changing the ownership, losing their markets and jobs and through process of reorganization on every level and at the same time trying to adjust their way of work to the challenges of the modern world. The situation in the Croatian plastics and rubber industry will be presented, its way of adjusting to the changing business conditions and the main organizational and managerial changes that occurred in the Croatian plastics and rubber companies during the process of transition.
Development of a Novel Micro Compounder for Polymer Blends and Nanocomposite
In this paper, we introduce a new type of small scale compounder. The compounder developed is for mixing of polymeric samples of 0.5 ~ 10 g. It consists of a heated cylindrical metal having two cylindrical cavities connected through a narrow channel and two cylindrical pistons, which squeeze molten polymers from one cavity to the other cavity through the narrow channel. During mixing procedure, the molten polymers flow from one cavity to the other cavity, repeatedly, and this operation generates the extensional flow in the converging and the diverging geometry. Because the compounder has mixing chamber of very simple geometry, the cleaning is very easy and the material lost is very small. We evaluated the mixing efficiency of the compounder by comparing with the commercialized small scale-mixers including a cup and rotor batch mixer, an internal batch mixer and a recirculating conical twin screw extruder. It was found that the compounder developed has many advantages over the existing small scale mixers.
Unique Properties of Polyaniline Nanorods Blends with Cyanoresin
Conducting polymer blends of polyaniline nanorods (PANI-NR) and cyanoresin were prepared by in situ polymerization. PANI-NR was synthesized by using the template free method and PANI-NR / cyanoresin blends were prepared by the addition of cyanoresin / dimethylformamide (DMF) solutions to PANI-NR / DMF solutions. Its morphological state has been confirmed. The diameter and length of PANI-NR obtained was approximately 120 ~200 nm and 600 ~ 1200 nm, respectively, and the conductivity of PANINR/ cyanoresin blends was 10-3~10-1 S/cm. The thermal stability of PANI-NR/cyanoresin blends was improved with increasing cyanoresin contents. The effect of dopant types and their blend compositions on the morphology and conductivity of PANI-NR/cyanoresin blends were investigated.
Enhancing the Mechanical Property of Polymeric Composites with Added Nanomaterial
The use of nano-particulates in plastic materials has become a potential alternative due to its versatility on property modification and the ease of batch fabrication. This paper investigates the kneading and mechanical properties of polypropylene added with nano-ZnO powder in sizes of, 10 to 30 nm, through batch kneading and microinjection molding steps. The results showed that the 1wt% ZnO made microgears with a 1.5 mm outer diameter were well duplicated with clear structural definition. The standard deviation in dimension was far less than the designed deviation of 20 ?m. The resulting composites exhibited significant improvement in wear resistance of 50% and mechanical strength of 40% with a small amount of nanofillers, 1wt% and 5wt%, respectively.
Applications of Thermoformability Analyzer
Thermoforming consistent parts depend on knowing and controlling several material and process variables, the most important being the quality of the sheet feed stock. The extruded sheet of the same material could vary in terms of polymeric contamination, thickness, thermal stresses, and amount of regrind, volatiles, color, gloss and grain. Mold material and mold temperature could also vary. Many times, effects of such variations manifest during actual thermoforming in form of tearing, wall thinning, shape distortion, fading, pinholes, and grain distortion. We illustrate use of novel equipment for rapid detection of such variables and their effects on thermoformability, sparring need for expensive plant time and material waste.
A Model for the Thermal Properties of Composites Containing the Ellipsoidal Inclusions
This paper proposes the solutions predicting the coefficient of the thermal expansion changes of composites which include the sphere, the fiber-like shaped and the disk-like shaped inclusions like two dimensional geometries, which has one aspect ratios, ?? = a1/a3. The analysis follows the procedure developed for elastic moduli by using the generalized approach of Eshelby’s equivalent tensor. This model should be limited to analyze the composites with unidirectionally aligned inclusions and with complete binding to each other of both matrix and inclusions having homogeneous properties.As the results, the coefficients of transverse thermal expansion of composites are predicted to increase more than the thermal expansion of polymer matrix for both disc- and fiber-like shape inclusions.
Effect of Carbon Nanotube on Properties of Poly(Ethylene 2,6-Naphthalate) Nanocomposites
Polymer nanocomposites based on poly(ethylene 2,6-naphthalate) (PEN) and multiwall carbon nanotube (MWCNT) were prepared by a melt blending process in a twin-screw extruder. The incorporation of MWCNT accelerated the mechanism of nucleation and crystal growth of PEN, this effect being more pronounced at lower MWCNT content. The non-terminal behavior of PEN/MWCNT nanocomposites was related to the dominant nanotube-nanotube interactions at higher MWCNT content, leading to the formation of interconnected structures of MWCNT in the polymer nanocomposites. The incorporation of a very small quantity of MWCNT significantly improved the mechanical properties of PEN/MWCNT nanocomposites.
Laser Absorption Coefficient Measurement of Amorphous Polymers for Laser Transmission Welding
Laser transmission welding is a technique that uses laser-absorbent and laser-transparent thermoplastics. The energy loss in the transparent part and the depth of laser penetration in the absorbing part depend on the laser absorption coefficient (LAC). This paper presents a novel LAC measurement method for use on absorbing parts. A defocus strategy was used to attenuate the power of the laser beam which was then passed through thin specimens prepared using a microtome. LAC of polycarbonate was measured for carbon black content from 0.0125 to 0.1 wt.%. It was found to increase linearly with carbon black concentration.
Thermoformable Thermoplastic Olefin (TPO) Blends
Among key success factors for thermoplastic olefins in automotive applications, the cost/part and processability are most important. Today, much of TPO is processed via injection molding. The drive for lighter and hence the thinner wall parts requires compromise between processability and properties. In shaping large parts, thermoforming offers significant advantages over injection molding. However, conventional PP and impact modifiers used in TPOs lack necessary melt strength and/or melt elasticity for thermoforming deep and thick wall parts. Modification is therefore deemed necessary. This paper summarizes properties of a new type of TPO produced via reactive modification with balanced stiffness, impact and thermoformability.
Plastic Automotive Components: High Solids Radiation Curable Basecoat and Clearcoat for Flexible Plastic Automotive Components
Commercially viable radiation curable basecoat/clearcoat systems have been the focus of considerable research over the past decade. Now, with the emergence of new classes of urethane acrylate oligomers, a flurry of activity is underway to develop coatings that have properties superior to conventional 1K and 2K automotive coatings. This paper will introduce a commercially viable radiation curable basecoat and clearcoat developed specifically for three dimensional plastic automotive components. These robust coatings meet or exceed all OEM performance specification. Further discussion will focus on the chemistry, performance testing (including natural and artificial weathering), processing, and commercial application of this much anticipated coating system.
High Temperature Issues for Polymer-Based Solar Thermal Systems
Use of polymer technology for solar thermal systems is perhaps the best strategy to achieve radical cost reduction. However, polymer materials durability is a key barrier to polymer-based systems, including affect of high temperatures. It is shown that stagnation temperatures in glazed flat plate collectors will rapidly degrade or melt commodity plastics, and overheat protection (OHP) must be employed. Normal operation and stagnation temperature frequency distributions are given, as needed for creep and other analyses. It is shown that venting-type OHP can reduce temperatures of the occasional stagnation events to below 100 C, which could allow successful commodityplastics- based solar thermal.
Correlations of Tensile Modulus for Polyethylene Blown Films with Microstructural Parameters
A series of blown films were produced by varying three key parameters: take-up ratio (TUR), blow-up ratio (BUR), and frost line height (FLH). The tensile properties of the resulting films were investigated in relation to their microstructure characteristics. The orientation parameters of the films were measured by XRD and birefringence. They were determined for both crystalline and amorphous phases. The crystalline content, the lamellar thickness and crystal sizes were obtained from DSC and WAXS pole figure technique. The SAXS technique was used to find the average length of the crystal and amorphous layers. A model for the tensile modulus was proposed and correlated to some structural parameters including crystalinity, orientation factors for crystalline c-axis and amorphous phase, lamellar thickness and crystal size. The measured modulus and calculated one were compared and a reasonable agreement was found between them.
Breakdown of the Cox-Merz Rule and Instability of Polymer Solutions in Viscometric Flows
There has been considerable interest in recent years concerning the instability of polymer melts and solutions in viscometric flows. Here we examine the flow instability in a polybutadiene solution and in NIST SRM 2490. The instability manifests itself as a deviation from the Cox-Merz rule that relates steady shear viscosity vs. shear rate with dynamic viscosity vs. frequency. We find that in all instances of deviation from the Cox-Merz rule investigated the fluid undergoes edge fracture and the deviations can be related to the edge fracture rather than to changes in constitutive behavior.
Correlation of Electrical Resistance and Electromagnetic Shielding for Thermoplastic Composites
Several commercially available electromagnetic interference (EMI) shielding thermoplastic materials were evaluated for electrical resistance and EMI shielding. International Electrical and Electronics Engineers (IEEE) test method 299 and ASTM D4395 shielding tests were performed as far field shielding tests. A ladder box configuration was used to evaluate near field shielding. Electrical resistance was measured along the surface and through the parts.It was found that type and fit of the correlation between shielding effectiveness and electrical resistance varied across the frequency sweep. Generally, it was found that through resistance provides a better correlation than surface resistance for all shielding tests. This may be due to the increased within test variability of surface resistance compared to through resistance.
Effect of Processing Parameters on Electrical Properties of Electrically Conductive Composites
The effect of injection molding parameters on electrical resistance and electromagnetic interference (EMI) shielding was examined for two commercially available grades of electrically conductive polycarbonate/acrylonitrile butadiene styrene (PC/ABS). A Box-Behnken design of experiments (DOE) was utilized for the variables of mold temperature, barrel temperature and back pressure. Surface resistance was measured to evaluate electrical conductivity. International Electrical and Electronics Engineers (IEEE) test method 299 was used to evaluate shielding effectiveness.Neither EMI shielding or surface resistance was changed in a significant way over the processing condition examined. A very weak trend is seen for one of the materials with mold temperature.
Comparative Study of New Generation Thermoplastic Elastomers and Polyester-Polyester Thermoplastic Elastomers
New generation thermoplastic Elastomers (Elastollan® HPM**) & Polyester-Polyester thermoplastic Elastomers (COPE) are block copolymers of hard and soft segments. The hard segments are semi-crystalline thermoplastic that act as physical cross-links which ties the amorphous elastomeric soft segments together. On one hand, the hard segment should have regular structure to promote crystallinity. On the other hand, the soft segment would have irregular structure and low glass transition temperature to promote low temperature flexibility. The melting point of the hard segment would influence the upper use-temperature of TPE, whereas, the glass transition temperature of the soft segment would influence the lower use-temperature of TPE.In this work HPM, are compared to traditional TPU and COPE. Several testing methods are used to compare the flow parameter, and physical & thermal properties of these materials. Melt-viscosity, tensile, tear, compression set, and long-term properties exemplified in hydrolysis resistance & oven aging are discussed and compared.
Long Term Performance of Polymers for Solar Hot Water Applications
Polymer materials used in domestic hot water heating systems must maintain mechanical properties in the working fluid over their target lifetimes. In potable water, chlorine and pH combine to create an oxidative environment, characterized by the oxidative reduction potential (ORP) that can chemically attack a polymer, resulting in permanent loss of mechanical strength and increase in creep compliance. Polymer morphology data and mechanical property data are presented for polysulfone (PSU), polybutylene (PB), polypropylene random copolymer (PP-r) and polyamide 6/6 (PA66) specimens that had been exposed to an aqueous oxidative environment. The data obtained after up to 1500 hours exposure in hot potable chlorinated water (ORP ranging from 550 mV to 825 mV), show that PSU and the polyolefins with antioxidant additives (PB and PP-r) maintain their mechanical properties, while PA66 degrades significantly.
A Mathematical Model for the Heat Sealing of Linear, Semi-Crystalline Polymers
A mathematical model and computer simulation describing the heat sealing process for linear, semi-crystalline polymer films has been developed. Accounting for the effects of conduction heat transfer with phase change, interfacial melting, and polymer chain scaling relationships based upon reptation theory to describe chain diffusion and strength development at the bonding interface during the transient, non-isothermal heat sealing process, the model demonstrates that interfacial melting, wetting, and chain interdiffusion are all important contributions to the development of the seal strength during rapid heat sealing. The model has been used successfully to compute the time dependence of interface strength development during the heat sealing process for linear polyethylene copolymers.
Polypropylene-Wood Plastic Composites Reinforced with Different Amounts of Wood and Organoclay
In this study, wood-plastic composites (WPCs) were made by compounding 10, 20, 30 and 50 wt% wood flour (WF) with a polypropylene (PP) / clay nanocomposite matrix using a co-rotating twin-screw extruder. A PP/clay master batch was diluted to give polymer nanocomposite (PNC) pellets having varying percentages of clay, and these pellets were then compounded with WF and a fixed amount of polypropylene grafted with maleic anhydride (PP-g-MA) that acts as coupling agent between wood and PP. The WPC pellets were finally injection molded into test specimens whose thermal and mechanical properties were measured and whose fracture surfaces were examined with the help of a scanning electron microscope (SEM). Results obtained were compared with results on WPCs containing additional WF but no clay. It was found that the addition of clay to PP enhanced the modulus of both the base polymer and the injection-molded WPCs. Also, the peak mass release temperature (PMRT) in TGA increased with wood and organoclay content.
The Effect of Pigment on Rotomoulded Polyethylene Powder and Micropellets
This paper presents the results from investigations into the differences in the rotational moulding and mechanical properties between pigmented polyethylene powder and micropellets. Both high shear and low shear pigment blending methods were examined, as were a range of pigment addition levels. This was followed by a series of mechanical and analytical tests on the rotomoulded articles to determine properties. Whilst micropellets tended to produce a different surface porosity than powder, few bubbles were evident within the wall thickness for both high shear and low shear blending. For high shear blending, with pigment addition levels up to 0.05%, similar impact properties were noticed for both powder and micropellets. Low shear blending resulted in more inconsistent impact values. There were also more visual inconsistencies in articles produced from powder.
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