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.
Roughly 1/3rd (1.3 billion tonnes) of the food produced in the world for human consumption gets wasted every year. Fruits and vegetables have highest wastage rates of almost 40-50%. This is partly due to ethylene action and improper storage and handling. Ethylene, a catalyst generated by climacteric fresh produce is responsible for their ripening. Ripened fruits have more risk of microbial spoilage due to increased sugar %. Improper handling, storage, lack of cold chain etc in post-harvest conditions further increases the loss. In the past, we have reported ?niche? technologies for fruit preservation, such as chemical agents responsible for adsorption and destruction of ethylene. In continuation, now we are introducing some more ?unique? technologies such as using a) Catalytic converters (of ethylene to ethylene oxide), b) Ethylene adsorbers and c) Halogen releasers. We believe that these simple and cost-effective techniques will be the trendsetters to reduce horticultural wastage considerably and in the end benefit the farmer, the retailer and also the consumer. Efficacy of these products was tested by using them as novel additives in flexible packaging, punnets etc. which are commercially used for storage and transport of various fruits and vegetables in which they were effective in reducing ethylene from the storage area. We also experimented use of these products by incorporating them in a plastic film and all through we could acquire considerable shelf life extension of both climacteric and non-climacteric fruits and vegetables. We firmly believe by using such value-added packaging post harvest horticultural losses will be considerably reduced and it can result in a service to mankind.
Cellulose acetate (CA) is one of the oldest plastics, with an application history dating back over 100 years. Recent drivers towards an engineered bio-based material that can be used in demanding applications have caused revitalization in CA product development. This paper illustrates the ability to fine-tuning mechanical and thermal properties through plasticizer selection. A case study is also presented where CA can be used to enhance the bio-content of the petro-based plastics such as polypropylene (PP) while improving performance of the final blend.
In the present work, poly (glycerol sebacate) elastomer was obtained by microwaving glycerol with sebacic acid during 128 minutes at 180øC. The power and the temperature were recorded through the reaction. They were unstable (oscillating) during the initial period of reaction (one hour), and become stable after. The step in which the power was unstable could correspond to the pre polymerization and the second step to the polymerization. Thermogravimetric analysis, attenuated total reflectance, and mass loss measurement during the process support this hypothesis.
Lightweight design is an essential part of the automotive strategy for reducing the CO2 emission. The use of carbon fiber reinforced polymers (CFRP) offers an enormous lightweight potential in comparison to aluminum, enabling a weight reduction, if a load-adapted (unidirectional) CFRP-design is used, of up to 60% in automobile parts without a degradation of the functionalities. Today, the use of CFRP is limited in mass series applications of the automotive industry by the cost of the conventional carbon fiber precursor Poly-Acrylic-Nitrile (PAN). Fifty percent of the cost of a conventional carbon fiber already belongs to the cost of the PAN precursor.
The analysis of lignin as an alternative precursor shows clearly a significant reduction in the cost of CFRP and reduction of CO2 emission during carbon fiber production. This fact is essential to make carbon fibers ready for a mainstream use within the automotive industry.
For qualifying Lignin as a precursor for automotive carbon fiber a detailed chemical understanding of the material is necessary. Lignin, which was used for carbon fiber production, is analyzed with the help of nuclear magnetic resonance spectroscopy and infrared spectroscopy in this paper, and the major chemical reactions during conversion process are highlighted.
Chemical modification of poly(lactic acid) (PLA) through a reactive extrusion process was performed in the presence of a free-radical initiator and multi-functional chain extenders. Batch foaming, using nitrogen as the blowing agent, was done at various temperatures to differentiate the effect of chain branching and nucleation on the cell size of reactively modified foams. Depending on the conditions very fine, sub-micron size foams were obtained in reactively modified PLA.
The biodegradable poly(lactic acid) (PLA)/graphene oxide (GO) nanocomposites were prepared successfully at various GO loading by solution casting. Wide angle X-ray diffraction (WAXD) showed the layered GO were exfoliated in the nanocomposites and well distributed. Evident crystallization peaks were observed in the PLA/GO nanocomsites rather than neat PLA in the nonisothermal melt crystallization test, which indicated the GO was an effective nucleating agent. For isothermal melt crystallization, the overall isothermal melt crystallization rates were signi?cantly greater in the nanocomposites than in neat PLA. The crystallization rates decreased with increasing crystallization tempera?ture. The incorporation of GO did not affect the crystal morphology of PLA in the nanocomposites, but it contributed to more regular and perfect crystallization structure.
Our industry leading separation technology enables us to recover styrenic and polyolefin plastics from complex mixed streams such as shredded waste electrical end electronic equipment. Plastic flakes recovered using our process are compounded and sold as pellets suitable for use in injection molding applications. This paper looks at the challenges and benefits of recovering plastics and modifying their properties for use in various applications such as home appliances, office products and electronics.
Recycling commodity plastics with non-stringent mechanical requirements present few technical changes other than justifying the cost of recycling. When considering recycled engineering plastics for high end products with very tough mechanical, cosmetic (including custom color), processing, cost and reliable availability requirements with minimal lot to lot variation, it becomes a much bigger challenge. This paper deals with a successful case study in overcoming these challenges.
In Japan, eggs are widely used in many food products on the market, and 200,000 tons of eggshells are annually discharged and most of them get discarded.
Re-use of discarded eggshells into food trays is one of the efficient ways to realize a recycling-oriented society.
Many food trays consist of polypropylene or polystyrene, and sometimes recycled products. Thus, it is possible to use biomass materials such as eggshells as a bulking agent. Eggshells need to be compounded into resin when used in food trays, but the egg?s unique sulfur smell is emitted when applying heat in the manufacturing process.
In order to solve this odor problem, we compounded under different conditions with polypropylene and eggshell to research ways to reduce odor.
The results suggested that molding temperatures exert significant influence on odor generation.
By molding at the lowest temperature that enables resin to mold, a possible countermeasure for odor reduction is created.
Poly(lactic acid) (PLA) and Poly(propylene carbonate) (PPC) polyol were melt-compounded to fabricate a novel polymer blend with balanced mechanical properties (tensile strength and ductility). Blend with 90wt.% PLA/10wt.% PPC polyol and 70wt.% PLA/30wt.% PPC polyol were prepared and evaluated in terms of mechanical performance. As for the blend with 30wt.% PPC polyol, two residence time have been applied (1min and 2min). It was found that 10wt.% loading of PPC polyol has an adverse effect on both tensile strength and elongation at break of the blend. Overall mechanical performance deteriorated with only 10wt.% PPC polyol. Major finding was that with incorporating 30wt.% PPC polyol in the polymer blend system, the ductility (elongation at break) of the blend significantly improved by 5000%. However, the tensile strength decreased drastically. The morphology of the blend was investigated through scanning electron microscopy (SEM).
The 2014 Sustainability Survey was the second survey that SPE Marketing and Management Special Interest Group conducted on sustainability in the plastics industry. The first survey was conducted in 2011. The purpose of this paper is to present the results of the 2014 survey, and establish some baseline case studies of best sustainability practices in the industry.
Poly (butylene adipate-co-terephthalate), (PBAT) and poly (butylene succinate), (PBS) are promising biodegradable polyesters whose blends have gained great attention in wide range of applications. However, there are some drawbacks to the use of these biodegradable polymer blends in durable applications. The main disadvantage of these materials is hydrolytic degradation at elevated temperature and humidity. In this study, we have assessed the durability of PBAT, PBS and PBS/PBAT blends at 50 oC with 90% relative humidity (RH) for duration of up to 18 days. The mechanical properties of these polyesters were evaluated before and after 18 days of conditioning at 50 oC with 90% RH. The mechanical properties of the polyesters were affected with increasing conditioning time. This can be attributed to the susceptibility of ester bonds to hydrolytic degradation at elevated temperature and humidity. The hydrolytic degradation was further confirmed by scanning electron microscopy
Polylactic acid (PLA), a bio-derived, biodegradable polymer, is being used as a substitute for conventional, non-biodegradable polymers in packaging applications. However, it has poor barrier properties for gases and water vapor, and these can be improved by dispersing nanoclay platelets in the polymer. In this work, the effects of adding nanoclay and a plasticizer, namely acetyl tributyl citrate (ATBC), on the water vapor permeability of PLA films have been evaluated; a variety of mixing methods were employed. It was found that while nanoclay addition can help in lowering the permeability through both the plasticized and unplasticized PLA, the effect was less than anticipated in the presence of the plasticizer. However, if the nanoclay dispersion was assisted by ultrasonication, the results in the two cases were comparable. In addition, it was found that the method of mixing during nanocomposite preparation also had significant effect on the permeability properties of the plasticized samples.
Scratch and mar damages can critically impact the aesthetics of polymeric surfaces. Improving scratch and mar visibility resistance of polymers is of big interest for academic and especially industrial arenas. In this paper, we investigate the influence of surface brightness, color and transparency on scratch and mar visibility resistance in polymers. A new psychophysical test based on Multidimensional Scaling (MDS) statistical method was utilized to determine mar visibility resistance onset. It has been found that scratch visibility resistance decreases with greener, lower brightness and higher transparency samples. Preliminary results show that MDS is a powerful tool to disseminate the psychophysical evaluation of mar damage. This research paves the way for a standardized methodology to reliably quantify scratch and mar visibility resistance in polymers.
The effects of catalysts p-toluenesulfonic acid (TsOH) on trans-reactions in poly (lactic acid) (PLA)/polyamide (PA11) blends were investigated in this study. The extent of reaction was tracked using solubility, modulated differential scanning calorimetry (MDSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FT-IR). The organic acid catalyst appeared to induce trans-reaction but also reduced overall molecular weight in PLA/PA11 blends. The interchange reactions appeared to compatibilize the blends as evidenced by calorimetry and microscopy.
Educational modules focused on bio-based polymers were successfully developed and implemented for undergraduate curricula. These modules included experiments for (1) synthesis of a biodegradable polymer, (2) characterizing the properties of this polymer and comparing these properties with those of a commonly-used petroleum-based polymer, and (3) melt processing a bio-based, biodegradable polymer. All modules were well-received by and produced significant learning by the undergraduate students.
As global leader in custom colored engineering thermoplastics SABIC is committed to investigating sustainable methods in process and analytical techniques. SABIC has long history partnering with customers to differentiate their products by developing desired looks and aesthetics for unique branding. SABIC and its COLOREXPRESSTM is therefore, capable in handling complex color matching, formulation to meet product performance and utilizing expertise in delivering long term product performance regardless of lot size.
Processors commonly use color concentrate or master batch for product coloring during molding or extrusion. This process involves modification of screw design or feeder for optimal product quality. Custom compounders such as SABIC use pigments with various polymers and additives, with optimized formulation, screw design, and feeding methods. Therefore providing customers with convenience and superior product performance than color concentrate or master batch.
General concerns include pigments dispersion, its effects on engineering thermoplastics properties and surface appearance. Theory behind agglomerate break-up and its effects on experimental molded samples are discussed in the paper.
For this study samples were produced using different pigment feeding methods including standard pigment compounding method and use of color concentrates. Also, SABIC?s proprietary method was compared. It is critical that pigments be evenly dispersed and distributed in the polymer matrix while maintaining consistent viscosity and optimal mechanical properties.
Commonly used pigments in polymers include titanium dioxide and carbon black. Typically color compounds incorporate more than one pigment which adds to the complexity. Experimental findings from the various compounding methods on mechanical properties, surface, heat/hydro aging and color appearance are presented. This paper also compares and reveals some superior pro
Two different recycled polyamide 6 resins were used in this study: post-industrial waste polyamide 6 (PIW) obtained from a fiber manufacturer; and post-consumer waste polyamide 6 (PCW) recycled from used carpets. Differential scanning calorimetry (DSC) and Dynamic mechanical analysis (DMA) proved the presence of polypropylene (PP) in PCW. Moreover, thermal gravimetric analysis (TGA) showed that PCW contained approximately 10 times more ash content than that of PIW. The PP and inorganic contamination of PCW come from PP carpet backing and calcium carbonate (CaCO3) filled latex binder, respectively . Due to higher inorganic filler content, PCW exhibited higher melt viscosity and also higher storage modulus than that of PIW. Tensile tests were performed on dog-bone specimens cut from injection molded plaques. PIW displayed approximately 20% higher tensile strength than that of PCW. However, a 70% drop in PCW vibration weld strength was observed. This is attributed to its PP contamination.
A biorenewable thermosetting polymer was synthesized by copolymerizing acrylated epoxidized soybean oil and tung oil using a free radical polymerization method. It is found that tung oil acts as a plasticizer in acrylated epoxidized soybean oil. This article presents a simple, versatile, and environmentally friendly technique to produce thermosets with a wide range of thermo-mechanical properties.
This study provides foundation for the development of a post-consumer recycle resin with low purity Post Consumer Recycle Polyamide 66 (PCR-PA66) and no delamination. These resin were developed using a novel concept of maximizing usage of low purity PCR-PA66 while maintaining part functionality. Main impurities in the PCR-PA66, which are calcium carbonate, latex, polypropylene, colorants and additives need to be taken into consideration to come up with a robust product. From these contaminants polypropylene (PP) present in the carpet backing and carried over in the PCR-PA66 stream causes serious potential for delamination and will be discussed in depth. A fixed amount of glass reinforcement provides part functionality, and total aim reinforcement was targeted to 36%. Delamination test was developed and this study aimed to uncover how to predict, measure and avoid potential of delamination while maximizing usage of low purity PCR-PA66. This paper describes the properties of optimized resins and boundary regions.
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