SPE Library

In this study, piezoresistive behavior of poly(hydroxybutyrate valerate) (PHBV)/multi-walled carbon nanotoubes (MWCNTs) composite has been discussed. Melt mixing technique was used to achieve maximum possible dispersion of CNTs in polymer matrix, as this process involves very high shear forces during mixing. The prepared composite shows gauge factor value of three which is very close to gauge factor value of conductive metals like copper and aluminum. Quasi-static and time dependent piezoresistance was investigated for the prepared composite. Environmental scanning electron microscopy was performed to observe dispersion of CNT in PHBV matrix.

Polylactic Acid (PLA) is a renewable polymer with many unique features including compostability. However, PLA suffers from several performance deficiencies which limit its market potential. A key deficiency is its ability to withstand elevated use temperatures above 55 ?§C. PolyOneƒ??s objective was to explore a range of approaches to identify a practical path to improved heat performance while seeking to maximize renewable content and processability. This paper addresses the industry need for a high renewable content polymer with practical heat resistance without relying on any additional thermal treatments such as annealing. Various PLA-based compounds were prepared and screened using DMA in an effort to correlate results to the heat distortion temperature (HDT) exhibited by injection molded PLA. It was concluded that polymer blends offered the greatest commercial viability of all the approaches considered under normal injection molding conditions. Multi-phase compatible polymer blends were found to have the most significant impact on blend properties. All components of the preferred blend composition are commercially available today. Heat performance can be tailored based upon performance requirements and bio-content objectives. The PLA content of the blends studied varied from 72% to 35%, while the corresponding HDT (under 0.455 MPa load) ranges from 57 ?§C to 101 ?§C. Potential increased bio-derived contents are also considered.

Polylactic Acid (PLA) is a renewable polymer with many unique features including compostability. However PLA suffers from several performance deficiencies which limit its market potential. A key deficiency is its ability to withstand elevated use temperatures above 55C. PolyOne’s objective was to explore a range of approaches to identify a practical path to improved heat performance while seeking to maximize renewable content and processability. This paper addresses the industry need for a high renewable content polymer with practical heat resistance without relying on any additional thermal treatments such as annealing. Various PLA-based compounds were prepared and screened using DMA in an effort to correlate results to the heat distortion temperature (HDT) exhibited by injection molded PLA. It was concluded that polymer blends offered the greatest commercial viability of all the approaches considered under normal injection molding conditions. Multi-phase compatible polymer blends were found to have the most significant impact on blend properties. All components of the preferred blend composition are commercially available today. Heat performance can be tailored based upon performance requirements and bio-content objectives. The PLA content of the blends studied varied from 72% to 35% while the corresponding HDT (under 0.455 MPa load) ranges from 57 ºC to 101 ºC. Potential increased bio-derived contents are also considered.

Polyaniline-clay (PANI-MMT) nanocomposites were synthesized through in-situ polymerization of polyaniline with various dopants. Those nanocomposites were used to blend with polystyrene (PS) to form an expandable composite resin, which will significantly impact the foaming process using a CO2 blowing agent. The material composition and foam morphologies were characterized through various analytical techniques, such as, X-Ray diffraction (XRD), SEM, dielectric measurement, UV/vis, and FTIR. Based on our experimental results, we are proposing that the de-doped base form" of Pani-MMT nanocomposites and both "inorganic and organic salt-form" Pani-MMT nanocomposites will act as a "molecular CO2 reservoir" to control the CO2 releasing during the foaming. The selection and optimization on those compounds will be enormously important for developing a new inexpensive and environmental friendly blowing agent for the foam industry to achieve the final goal of replacing the existing CFCs /HCFCs /HFCs blowing agents!"

The major objective of this research was poly(lactide) (PLA) toughening using two impact modifiers (IMs). IM1 was derived from biodegradable resource and IM2 was non-degradable ethylene-acrylate copolymer. Blend films were prepared using a single screw extruder, and their mechanical properties were measured using tensile testing. Results showed that the Young's modulus did not change significantly with increasing concentration of IM1, but decreased with IM2 concentration. The maximum elongation at break was 240% for IM1 at 8 wt% loading and 255% for IM2 at 12 wt% loading. Clarity of the films decreased with higher additive concentrations for both IMs, but IM1 gave clearer film than IM2 for given composition. AFM images showed IM1 dispersed in PLA as isolated islands at lower compositions and transitioned to short threads at higher compositions; IM2 existed mostly as islands. Annealing of the films at 100 ?§C for 1 h increased the percent crystallinity, but did not affect the mechanical properties significantly.

This work studied bio-plastics such as polylactic acid (PLA) and protein based plastics form corn and compared to petroleum based plastics such polyethylene (PE) and polystyrene in terms of their ecological as well as economical performance from a “Cradle to Grave” perspective. This study included energy input emissions output of green house gases and costs from their life cycle steps of raw material acquisition to the final product disposal. It was found that products manufactured from bio-based feedstocks were relatively higher in cost they resulted in less green house gas emissions.

A new injection molding for metal powder green part was put forward in detail in this paper. Vibration force field generated by electromagnetic field in the whole process of plasticization, injection and packing, implementing dynamical plasticization metering, injection and packing was introduced. An in-depth experiment study on the effect of vibration force field on metal powder 316L/binder under steady and dynamic injection conditions was carried out with an experiment equipment and dynamic injection machine. Experimental results show that the filling pressure will be reduced when the vibration is introduced, the flow of melts becomes more uniform and the distribution of different components is also more uniform in the green parts during the dynamic injection molding. The mixing dispersion and distribution effect are better and the density is also larger than the green part's with traditional injection molding. The existing of vibration can effectively promote not only the microcosmic structure and also quality of metal powder green part.

Life cycle analysis (LCA) is an accepted methodology to determine the environmental impact of a certain material or package at different stages in its product life. In some cases, however, LCAs can be complex and expensive to carry out. DuPont is looking at ways to internally estimate the LCA of its products by using a modular approach: building estimates of nonrenewable energy and green house gas emissions by summing proprietary information on our ingredients and unit operations. The output of this tool will be used to target our internal improvement efforts and potentially help our value chain partners make better multilayer flexible packaging design choices.

Life cycle analysis (LCA) is an accepted methodology to determine the environmental impact of a certain material or package at different stages in its product life. In some cases however LCAs can be complex and expensive to carry out. DuPont is looking at ways to internally estimate the LCA of its products by using a modular approach: building estimates of nonrenewable energy and green house gas emissions by summing proprietary information on our ingredients and unit operations. The output of this tool will be used to target our internal improvement efforts and potentially help our value chain partners make better multilayer flexible packaging design choices.

Halogenated additives have long been used toenhance the flame-retardant properties of plastics.Recently, after many years of growing concern over theenvironmental and human impact of the disposal ofcertain halogen-containing products and theirincompatibility with recycling operations, leading globalelectronics manufacturers have begun moving to eliminateor sharply reduce the use of certain halogen-containingingredients in their products. DuPont is meeting the needsof these and other environmentally consciousmanufacturers with a growing range of engineeringpolymer grades using non-halogenated flame retardantsystems. This paper shows that they can fulfilldemanding requirements for strength, toughness, hightemperature resistance and processing efficiency.

Polycarbonates find applications in food industries due to their clarity and ductility. Sometimes failure of a polycarbonate part occurs. In food blender jars molded from polycarbonate, cracks were observed in the sealed joint only a few days after assembly. The root cause was investigated via microscopy, FTIR and GC-MS analyses. It was determined the cracks initiated and radially propagated from the bottom raised lip of the part. The root cause was a combination of a high stress in the lip region due to molding and design, and environmental chemical compounds, i.e., esters from a melt nut used in the assembly. The failure was typical environmental stress cracking (ESC) problem.

PAI (Torlon) is used in aerospace applications requiring excellent mechanical properties at high temperature, fluid resistance, and thermal stability. PAI is a delayed cure thermoset that reaches its ultimate properties and maximum Tg only with an extended postcure. This work examined the correlation of Tg and properties of four injection molded lots of PAI. Testing consisted of impact strength measurement, tensile and flexural strength and modulus testing at various temperatures and after different environmental conditioning. CTE in three orthogonal directions were measured and creep testing was run on samples after different environmental exposures, including long-term aging in turbine oil.

Recent advances have rendered bio-based and biodegradable PHB (poly hydroxybutanoic acid) copolymers suitable for many extrusion applications. The high molecular weight and narrow distribution of melt relaxation times of these polymers can sometimes cause sharkskin melt fracture to occur during extrusion. This may be a limiting factor for their wide-spread applicability. This presentation will discuss the characterization of sharkskin melt fracture of these polymers using capillary rheometry including the identification, for the first time, a critical criterion for their occurrence.

Kaneka Corporation has developed a silicone based flame retardant for Polycarbonate, Kane Ace MR-01. MR- 01 realizes non-bromine and non-phosphorus flame retardant PC compound and increases low-temperature impact strength. Kaneka's renowned graft polymerization technology makes it possible to disperse the cross-linked silicone particle into Polycarbonate matrix. MR-01 achieves V-0 in UL-94 protocol at 1.2 mm thickness (Kaneka's evaluation data) with a small amount of PTFE. MR-01 also has excellent thermal stability, which provides with superior impact strength retention after heat aging, and maintains the flame retardancy after recycling process.

Traditionally body panels of Heavy Commercial Vehicles (HCV) are built in Sheet Molding Compound (SMC) or metal. OEMs are looking for fuel-efficient, lightweight and greener technology solutions.The specific gravity of Engineering Thermoplastic (ETP) is much lower and offers significant weight reduction opportunity over SMC/metal. This paper presents limitations of SMC, key challenges in terms of aesthetics and high flow length to thickness ratio in processing HCV body panels with ETP.Show how these are solved through novel thickness distribution, feed system and process design.It is highly essential to design with plastic friendly concepts and to build the tool for balanced filling, no aesthetic defects, minimum pressure and tonnage. Predictive engineering is the best tool to use at the design phase to achieve first time right.

Traditionally body panels of Heavy Commercial Vehicles (HCV) are built in Sheet Molding Compound (SMC) or metal. OEMs are looking for fuel-efficient lightweight and greener technology solutions. The specific gravity of Engineering Thermoplastic (ETP) is much lower and offers significant weight reduction opportunity over SMC/metal. This paper presents limitations of SMC key challenges in terms of aesthetics and high flow length to thickness ratio in processing HCV body panels with ETP. Show how these are solved through novel thickness distribution feed system and process design. It is highly essential to design with plastic friendly concepts and to build the tool for balanced filling no aesthetic defects minimum pressure and tonnage. Predictive engineering is the best tool to use at the design phase to achieve first time right.

New ionomers have been developed to afford exceptional soft feel, high flexibility, and good scratch resistance. The thermoplastic characteristics enable ease of melt processing, good adhesion to various substrates, HF weldability, and deep draw thermal forming. The new ionomer is optically clear and glossy, and can be colored and printed. It has good compatibility with various pigments and additives for enhanced esthetic effects and outdoor weatherability. The soft feel and scratch resistance, coupled with the versatile processibility, make the new ionomers well-suited for protective and decorative applications. It contains no intentionally added halogen and can be recycled or incinerated to serve as an environmentally friendly alternative to flexible PVC or a lower cost alternative to flexible TPU.

Solid-state shear pulverization (SSSP) can lead to in situ mechanochemistry and enhanced dispersion relative to melt-state processes. SSSP of poly(ethylene terephthalate) (PET) results in low levels of branching and enhanced dispersion of heterogeneous nuclei, leading to increased melt viscosity and crystallizability, providing a solution to the problem of recycling PET for high-value applications. (PET undergoes molecular weight reduction during melt processing.) Adding 1 wt% microcrystalline cellulose to poly(lactic acid) (PLA) via SSSP can lead to major enhancements in crystallizability and materials with increased heat distortion temperature relative to neat PLA.

When it comes to resin drying, energy consumption is quickly becoming a key factor in the decision making process for one technology over another. However, drying energy consumption has several elements and key factors that affect the overall energy use of a dryer. It is a combination of heat-up energy and sustainable drying energy that are the elements that will, in the end, affect how much it costs to dry your resin on an annual basis.A uniform industry test standard would define the air capacity, basic load and kWh/unit of material. An industry test standard would allow users to plug in there given material, throughput and local energy rate, to calculate the true annual energy cost.

From sterilization to use, medical device packaging must provide a microbial barrier for the devices they protect. Reliability of this packaging is of the utmost importance since packaging materials must endure folding, rubbing, and a host of other mechanical and environmental stresses that can challenge the barriersƒ?? integrity. Pouches consist of flashspun high-density polyethylene (FS-HDPE) sheeting and laminates films composed of polyolefins and nylons. Case studies regarding sterile pouch failures that occurred at various stages of qualification testing and solutions for mitigating failures are presented. Common failure modes and mechanisms are discussed in detail.