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Recycling

Various topics related to sustainability in plastics, including bio-related, environmental issues, green, recycling, renewal, re-use and sustainability.

Eco-friendly Bio-based Adhesive Tapes made from Biomass Materials

Brett Herrick, Tetsuo Inoue, Shigeki Ishiguro, Satomi Yoshie, Akiko Tanaka, Hiroki Senda, Hitoshi Takahira, May 2013

There are some bio-based plastic films however some properties of the films should be modified to use as adhesive tape film and adhesive compound materials should be designed. We improved film properties by adjusting the sheeting process. Regarding the film, it was confirmed that poly lactic acid (PLA) film, which has good heat resistance and tear strength, was obtained by using the calendar sheeting process. On the other side, low glass transition temperature materials and crosslinking materials were selected and formulated for adhesive polymers. Developed bio-based adhesive tape was evaluated and compared to conventional acrylic adhesive tape, and comparable properties were obtained. In addition, in the case of surface protection tape, it indicated enhanced properties. We can introduce Eco-friendly Bio-based Adhesive Tape made from biomass materials.

Effect of D-content on CO2 solubility in PLA

Syed H. Mahmood, Chul B. Park, May 2013

The pressure-volume-temperature (PVT) behavior of Poly Latcic Acid (PLA) with dissolution of CO2 was investigated using an in-house visualization device; experiments were carried out at 453 K and 473 K, and pressure was varied from 6.894 MPa to 20.684 MPa. The results indicate that as the temperature increases, the swelling decreases, whereas an increase in pressure results in an increase in swelling. The effect of molecular weight (Mw) on swelling volume was also investigated by experimenting on different grades of PLA with varying Mw. The result is that molecular weight does not have a pronounced effect on swelling volume. The effect of talc on swelling ratio was observed by the addition of 5% talc content in PLA 3001D. A comparison was made between theoretical and experimental swelling volume ratios; the theoretical data was obtained using SS-EOS and SL-EOS.

Effect of Extensive Recycling on Flow Properties of LDPE

Huiying Jin, Joamin Gonzalez-Gutierrez, Pavel Oblak, Barbara Zupan?i?, Igor Emri, May 2013

Low density polyethylene (LDPE) was exposed to one hundred (100) consecutive extrusion cycles to simulate the process of mechanical recycling. Collected samples were characterized by means of melt flow index measurements and small amplitude oscillatory measurements to investigate flow properties. The results suggest that thermal degradation and gelation of LDPE occur after extensive extrusion which leads to simultaneous chain scission and crosslinking of the polymer chains. However, after 40 extrusions crosslinking is more dominant than chain scission. Rheological observations were confirmed by solubility studies that showed a pronounced increase in insoluble fraction after 40 extrusion cycles. This indicates that the technological parameters should be modified when processing recycled LDPE, particularly after 40 extrusion cycles.

Effect of mixing time and temperature on the rheology and morphology of immiscible polymer blends prepared from polytrimethylene terephthalate [PTT] and polyamide 6,10 [PA6,10]. Kevin Lucero, Marissa

Kevin Lucero, Marissa Tierno, Richard L. Lehman, Giorgiana Giancola, May 2013

Thermoplastic immiscible polymer blends were prepared from polytrimethylene terephthalate [PTT] and polyamide 6,10 [PA6,10] by melt processing in a Brabender mixer to assess morphology developed between the immiscible domains. PTT and PA6,10 were selected as a pair of engineering polymers with complementary properties and as a blend prepared to significant extent from bio-based precursors. Overall, a 50/50 blend of these polymers has a renewable content of nearly 50%. The overall objective is to develop an engineering blend with good stiffness, strength, and dimensional stability while simultaneously being easy to process. In the present phase of the work, blend homogeneity was studied as a function of mixing time and temperature in the range of t=0-25 minutes and T=240-260 C. Results are presented in terms of torque versus time and temperature curves that are interpreted in terms of domain formation and SEM micrographs are used to define domain size and overall morphology.

Effect of Molding Conditions on the Weld Line Property of Injection Molded Jute/PP Composites

Wang Cuntao, Yang Yuqiu, Hamada Hiroyuki, May 2013

Jute fiber is of not only low density and good mechanical property but also natural and degradable property. On the other hand, recyclable Polypropylene (PP) was also good choice for environmental friendly material. Injection molding is one of the most important processes to manufacture plastic composites because it is of high quality products with low cost. However, weld lines are unavoidable when two separate melt fronts rejoin during injection molding. The presence of weld lines not only detracts from the surface quality but also significantly reduces the mechanical strength of injection- molded parts. Although it is not always easy to completely eliminate weld lines, the weld line strength could be improved through suitable adjustment of molding conditions such as melt temperature, mold temperature, hold pressure, injection speed, and so on. Therefore, in this paper the weld line property of injection molded jute/PP dumbbell shape specimen was investigated. Pultrusion technique was adopted to fabricate jute/PP long fiber pellets (LFT) and the re-compound pellets of LFT, i.e. RP was made to improve the fiber distribution. Then LFT, RP were used to mold dumbbell shape specimens with or without weld line. In particular, the influence of back pressure and holding pressure on weld line strength of injection molded jute/PP dumbbell shape specimens was discussed based on tensile test and SEM observation.

Effect of Poly(Butylene Adipate-Co-Terephthalate) Contents on Crystallization and Mechanical Properties of Polymer Blends of Poly(Lactic Acid) and Poly[(Butylene Succinate)-Co-Adipate]

Sommai Pivsa-Art, Sorapong Pavasupree, Narongchai O-Charoen, Supaphorn Thumsorn, Weraporn Pivsa-Art, May 2013

The effect of poly(butylene adipate-co-terephthalate) (PBAT) contents on crystallization and mechanical properties of poly(lactic acid) (PLA) and poly(butylene succinate-co-adipate) (PBSA) blend was studied. PLA and PBSA were blended in a twin screw extruder, which incorporated PBAT as a ternary component in PLA/PBSA blend. The ratio of PLA/PBSA was set at 80/20. The contents of PBAT were varied from 0 to 50 wt%. The thermal properties and crystallization behavior of PLA/PBSA/PBAT blends were analyzed by differential scanning calorimetry. The effect of PBAT contents on non-isothermal crystallization kinetic of the composites was investigated by using Avrami equation. Tensile modulus and tensile strength of the PLA/PBSA blends decreased when increasing PBAT contents. It can be noted that the addition of 20 wt% PBAT showed the maximum impact performance of the PLA/PBSA blends.

Effect of Rice Flour Filler on Heat Seal Strength for Sustainable Designed Sealant Film

Ken Miyata, Motohiro Noguchi, Akihiro Nishioka, Tomonori Koda, May 2013

The packaging materials are spoiled in a short cycle. An environment packaging materials are demanded. The economic cost is one of problems to substitute general plastics for bio-resource sustainable plastics. In this study the potential of rice flour as compounding filler for sealant polymer was examined. Poly(butylene succinate)(PBS) / rice flour composite biodegradable film was processed directly by twin-screw extruder equipped with T-die. Heat seal property of the biodegradable film was investigated. As compounding filler material, the potential of rice flour on heat seal property was studied. At 100 ºC of heat seal temperature, the PBS / rice flour composite film showed high heat seal strength comparing with neat PBS film. By scanning electron microscopy observation, bled out rice flour grains at film surface affected heat seal property. The PBS / rice flour composite film could keep more than 80% tensile strength comparing with neat PBS. However heat seal strength for HDPE / rice flour composite film dropped. To attain high seal strength it needed longer dwell time. The compounded rice flour prevented heat seal property for HDPE. The exposed rice flour particles worked effectively for PBS / rice flour composite film.

Effect of Stereocomplex Crystallite as a Nucleating Agent on the Isothermal Crystallization Behavior of Poly (L-Lactic Acid)

Eunhee Kim, Hyun-sup Lee, Jong-Duk Kim, May 2013

Isothermal crystallization behaviors of poly (L-lactic acid) (PLLA) blended with different contents of Poly (D-lactic acid) (PDLA) were studied by wide-angle X-ray diffraction, differential scanning calorimetry and polarized optical microscopy. PDLA molecules added to PLLA formed stereocomplex crystallites in the PLLA matrix. The stereocomplex crystallites stayed unmelted at 190 °C and embedded in the PLLA molten matrix. Isothermal crystallization measurement at 100 °C revealed that the crystal radius growth rate decreased with an increase in the isothermal crystallization temperature. The spherulite growth rate has a peculiar PDLA concentration dependence. PLLA crystallization behavior might be affected by network structure and homogeneous dispersibility of stereocomplex crystal.

Effect of Talc Filler on Recycled PET Blends Injection Moldings

Kazushi Yamada, Hiroyuki Hamada, Shuhei Tamada, Noriaki Kunimune, May 2013

Recycled PET (RPET) is known to exhibit brittle behavior in the presence of notches. Therefore, we tried to improve the toughness and other properties of RPET by incorporating E-GMA, talc filler and engineering plastics as an impact modifier and talc to increase the rigidity and heat distortion temperature of RPET. As a result, these blends with E-GMA exhibited significantly higher stiffness and strength especially with increasing E-GMA content. In addition, these blends with talc filler indicated the high heat distortion temperature due to increase the crystalinity of RPET blends. Therefore, it was found that talc played an important role in enhancing the heat resistance of RPET. Some injection molding parts, i.e. tray, chopstick, and so on, were produced from these compound materials.

Electrical Properties of Polypropylene Composite Foams Reinforces with Long Stainless Steel Fibers

Aboutaleb Ameli, Mehdi Saniei, Davoud Jahani, Chul B. Park, May 2013

Conductive thermoplastic composite foams are a novel class of materials that can be an excellent candidate for producing cost-effective and lightweight products. In this work, electrically conductive polypropylene (PP) foams of various densities filled with varying contents of long stainless steel fibers (SSF) were successfully fabricated. The foaming of composites was achieved using a batch process and supercritical CO2 as the environmentally benign physical blowing agent. The PP-SSF foams maintained high level of electrical conductivity over a wide range of density reduction, depending on the initial loading of SSF. To better understand the conductivity behavior of solid and foamed composites, statistical percolation analysis was conducted. The analysis showed that the conductivity change with the foam density followed the percolation power law. The critical SSF concentration, calculated based on the sample’s final volume was 0.37 and 0.28 vol.% for the solid and foamed composites, respectively. In the current PP-SSF system, foaming decreased the weight up to ~70-80 % and lowered the percolation threshold by about 25%.

Evaluation of Heat Transfer Conditions to the Mold Temperature Stabilization in the Injection Molding Process

Joonsung Tae, Janghwan Kim, Jinsu Gim, Hyungpil Park, Byungohk Rhee, May 2013

In order to keep the part quality under a stable mold temperature, a number of parts should be discarded until the mold temperature reaches to a stable condition. Depending upon process and environmental conditions, the time to a stable condition varies. In this work, influencing factors to the stabilized mold temperature condition are examined. The results show that ambient temperature significantly affects the stabilization time. To predict the stabilization time with consideration of heat transfer to the molding machine, heat sink attached model in the CAE analysis was suggested. It shows a good agreement with experimental result.

Evaluation of Mechanical Property and Flame Resistance on Bio-Based Polymer Compounds

Hiroyuki Nishimura, Nobuyuki Imamura, Hiroki Sakamoto, Yuji Higuchi, Shinichi Kawasaki, Takahiro Nishino, Masayuki Okoshi, Hiroyuki Yamamoto, May 2013

This paper describes the evaluation of the mechanical properties and flame resistance on bio-based polymer compounds of Poly (lactic acid) (PLA) and Polyamide 11 (PA11). A compounding technology and mechanical properties of PLA and PA11 using a compatibilizer were firstly studied to improve the thermal resistance and the impact strength of PLA. Some compositions of PLA/PA11 blends using a compatibilizer were investigated. After some flame retardants which were not halogenated and toxic materials were blended to the composition of PLA/PA11/compatibilizer, the mechanical properties and flame resistance were also evaluated as compared with the commercialized PLA and Polycarbonate (PC) alloy. The flammability test was conducted with the multi-cone calorimeter to obtain the relation between the heat release rate or the integrated heat release value and the combustion time.

Failure of HDPE Butt Fusion Joint Due to Poor Manufacturing Practices

Ahamed Shabeer, Gerald F. Zamiski, May 2013

High density polyethylene (HDPE) pipes have been used successfully in applications ranging from potable water lines to chemical fluid transmission for nearly four decades because of its superior mechanical and chemical properties over other thermoplastic piping materials. The standard method of joining HDPE pipe in the field is the butt fusion process. The quality of the butt-fused joints depends largely on environmental and joining surface conditions. The failure modes commonly observed in butt fused joints are poorly fused and contaminated joints and initiation of cracking at stress concentration defects in the fusion weld. In this paper, a case study of fusion joint failure in a fabricated elbow fitting due to poor manufacturing practices is presented. The mechanism and type of failure have been deduced from a detailed morphological examination of the fracture surface. Various factors responsible for a brittle failure of the butt fused joints have been identified. Analytical and thermal testing was performed to identify a specific material characteristic responsible for the failure.

Foaming of Cellulose Fiber Reinforced Polylactic Acid Composites: The Effect of Cellulose Fiber Type

Wei Dan Ding, Pei Yu Kuo, Takashi Kuboki, Chul Park, Mohini Sain, May 2013

This paper investigates the effect of fiber type and fiber content on the foaming behaviors of cellulose fiber reinforced polylactic acid composites. Two types of cellulosic fibers with different sizes were used: micro- and nano-sized fibers. The composites were prepared by a film casting and hot pressing method and then foamed via a batch foaming process with CO2. The morphology and volume expansion ratio of the samples with different cellulose fiber contents were compared. The results suggested that micro-sized fibers had negative effects on the foam morphology and nano-sized fiber positively influenced the foam morphology. It is speculated that the crystals generated around the fibers affected the cell morphology significantly.

Fracture Behavior and Mechanical Property of Jute-Glass Hybrid Composite

Ryuiti Nishida, Zhiyuan Zhang, Yuqiu Yang, Hiroyuki Hamada, May 2013

Jute fiber has gained extensive use in recent years due to its advantage in environmental protection, low cost and low density. However, the limitation of its low mechanical property affects its application. Because of this reason, jute-glass hybrid fiber configuration was considered as an improvement. In this study, 2 kinds of jute-glass hybrid fiber configuration were employed to investigate the mechanical property and fracture behavior in different configuration. At the same time, different plies and different angle of the composite were analyzed. It was found the composite fabricated by B type fabric expressed better properties both on tensile and bending test. Scanning electron microscope observation was also found excellent matching between jute fiber and glass fiber in B type composite.

Halogen Free Polyphenylene Sulfide for Consumer Electronics Applications

Rong Luo, Xinyu Zhao, May 2013

The recent push for environmentally friendly halogen?free products has resulted in significant changes in the of polymer materials used in consumer electronics industry. A series of halogen free polyphenylene sulfide (PPS) products were developed to enable consumer electronics original equipment manufacturers and their suppliers to design and make products that will comply with halogen?free industry standards. These halogen free PPS products offer inherent flame retardancy (UL-94 V0), high flow suitable for small connectors, and high dimensional stability for metal over molding parts without loss of superior mechanical properties.

Heat Seal Characteristic of Environmental Friendly Films From Thermoplastic Rice Starch Filled Poly(Lactic Acid)

Supaphorn Thumsorn, Kazushi Yamada, Sommai Pivsa-Art, Ken Miyata, Hiroyuki Hamada, May 2013

An environmental friendly biodegradable polymer film was prepared from poly(lactic acid)/thermoplastic starch (PLA/TPS) blend by cast film process at 0, 5 and 10 wt% of TPS. The PLA/TPS blend films were heat sealed by a heat seal tester at a heat bar temperature of 90 and 100 °C. The heat seal time was varied from 0.5 to 2.0 s with a constant seal pressure of 0.2 MPa. The effect of heat seal conditions on heat seal properties of PLA/TPS films was investigated. Heat sealed strength was carried out by peel testing. Differential scanning calorimetry was used to analyze thermal properties and crystallinity of the heat sealed PLA/TPS films. From the results, heat sealed strength of PLA/TPS blend films decreased when increasing the heat sealed times. PLA films was peelable at the heat sealed temperature of 90 °C. PLA/TPS heat sealed films exhibited greater crystallinity than the PLA heat sealed film.

High Performance Thermoplastic Vulcanizates Based on Natural Rubber by Electron Induced Reactive Processing

Manas Mondal, Uwe Gohs, Udo Wagenknecht, Gert Heinrich, May 2013

Electron induced reactive processing (EIReP) – an eco-friendly and sustainable reactive processing method based on the use of high energy electrons - was used for cross-linking of the elastomeric domain during melt mixing in order to prepare natural rubber (NR) and polypropylene (PP) based thermoplastic vulcanizates (TPVs). The electron treatment with various absorbed dose values showed a prominent effect on mechanical, rheological, and morphological characteristics of the PP/NR TPV. SEM and TEM studies confirmed that these TPVs can exist across the co-continuous or discrete phase morphology. The maximum set of mechanical properties (tensile strength of 15 MPa and elongation at break of more than 500 %) were obtained at an absorbed dose of 100 kGy for a 50/50 blend ratio of NR and PP without any addition of compatibilizer or chemicals. At higher absorbed dose values the degradation of polypropylene showed a negative impact on the mechanical properties of the TPVs. Depending on the morphology and the results of tensile test a structure-property co-relationship is drawn on the basis of common phenomenological understanding of the TPVs.

High Recycle Content PBT/PC Product Development

Yuzhen Yang, Angelika Clark, Tianhua Ding, May 2013

PBT/PC blends provide an excellent balance of chemical resistance, mechanical strength (especially at low temperature), and processability for a wide range of applications. Recently, appliance applications started to demand more sustainable, environmentally-friendly and green materials without sacrificing any properties for their new generation products. To respond to this market requirement, a high recycle content PBT/PC blend with excellent chemical resistance properties, good FR performance, and great mechanical properties was developed. The use of a high recycle based PBT/PC blend is the key to opening a new door to the more sustainable and green world for future appliance applications.

Impact Modification of PLA Using Biobased, Biodegradable Mirel PHB Copolymers

Raj Krishnaswamy, May 2013

This work will focus on an approach to improve the impact toughness of poly (lactic acid) or PLA without compromising the biobased carbon content and compostability of PLA. Specifically, low-crystallinity and amorphous PHB copolymers were demonstrated to be very effective in improving the toughness of PLA at modest loading levels of 10-20 weight percent. This presentation will also compare the above approach with urethane, butadiene and acrylic impact modifiers along with the impact modification provided by other compostable polymers such as PBS and PBAT. Of particular significance is the extent of impact modification provided by an amorphous PHB copolymer (M4300 @ 10-20% loading) wherein the blend demonstrates a combination of mechanical properties that rival those of some engineering thermoplastics. Morphological considerations for the observed improvement in impact performance will also be highlighted.