SPE Library

A method to synthesize strongly acidic cation-exchange resins from porous styrene-divinylbenzene copolymers can quickly monitor porosity and significantly reduce cost, health risks, and pollution.

Poly(lactic acid) optimized with chain extenders, plasticizers, and nucleating agents forms stable and defect-free films with improved mechanical properties.

Polyaniline-magnetite nanocomposites can efficiently remove Cr(VI) from polluted water, be retrieved easily with a magnet, be regenerated with acid, and be reused for further Cr(VI) removal.

The purpose of this study is to determine how plastic-packaging companies define sustainability or sustainable practices and communicate sustainable practices to its target audience e.g., customer, consumer. There are two research questions this study intends to answer. First, how do such companies define sustainability or sustainable practices, and second, what persuasive appeals are used to communicate sustainable practices to their audiences via a company website?

The usage of waste tire rubber crumb as a dispersed phase in a thermoplastic matrix has been a topic of study for a long time. In order to obtain ‘value added products’ from polypropylene (PP) and waste ground rubber tire (GRT) crumb composites, the use of compatibilizers was found to be essential. The properties achieved remained inferior and thus GRT based thermoplastic elastomers (TPE) have limited applications. Due to similar reasons not many studies have been carried out on blending devulcanized rubber (DR) and plastics. However, DR being relatively more similar to virgin rubber is expected to perform better than GRT and result in improved properties as compared to GRT. This work expands our previous effort on a statistical analysis of compatibility between DR and PP, and the effectiveness of a sulphur cure system in compatibilization. We further study the role of a peroxide based cure system in detail with respect to compatibilization efficiency.

Applications, such as sheet and pipe, often require polymers that can resist abrasion during use. This is especially true if the application is to handle a slurry or grit. Although typical HDPE resins have good resistance to abrasion and can be broadly used with different chemicals, there are several applications that need a resin with improved abrasion resistance and good chemical resistance. For example, HDPE pipes designed to handle gritty water based slurries, such as mining slurries, may not be adequate to handle petroleum based slurries. This is especially true if the application is normally at an elevated temperature such as 60 degrees C. This paper discusses the evaluation of various HDPE resins and shows their differences in relationship to the environmental parameters encountered in slurry handling applications along with the processing parameters needed for manufacture. The different HDPE resins were tested at RT, 40 and 60 degrees C and at different immersion times in water and solvents. After the immersion conditioning, the resins were then abrasion tested. A modified HDPE resin shows acceptable abrasion resistance at both room temperature and elevated temperatures in both water and solvent based slurries. Evaluation of processability parameters were undertaken using melt index, spiral flow, and both lab and production extrusion equipment.

The ability of maleic anhydride grafted polymers to compatibilize non-polar polyolefin polymers with polar polymers or contaminants has been confirmed and publicized by a number of experts in the field. This study reports on a new generation of random copolymers of ethylene and anhydride functional monomers specifically designed for compatibilizing blends of polyethylene polymers with polar components (other polymers or additives) in mixed recycle streams. The results show that these copolymers, with a very high level of reactive functionality (>3% wt. of anhydride), improve the impact strength of molded or extruded part made from mixed recycle streams containing Polyethylene Vinyl Alcohol (EVOH) or Polyamides (PA) even when the scrap contains high levels of moisture, lubricants or other resins. Two practical examples are discussed: use in regrind layers of extrusion blow molded containers and use in recycling of mixed polymer streams to produce other parts.

Attention has recently become focused on the performance advantages of nanocomposites, and particularly polymerbased nanocomposites with respect to incumbent “neat” polymers or metallic materials for lightweighting initiatives. In the interest of sustainability, the specific use of bio-reinforced nanocomposite parts and nanostructured coatings within automotive, aerospace, construction, medical and packaging applications is accelerating. These “green” nanocomposites can provide high mechanical strength at low density, low weight, and low cost while generating low carbon dioxide emissions. However, there are interfacial surface adhesion challenges with these and other nanocomposites, in addition to particle distribution and stability issues, which can inhibit full realization of their mechanical performance advantages. This paper will profile polymeric nanocomposites and nanocoatings, as well as define surface modification protocols using atmospheric pressure plasma technologies to optimize interfacial adhesion to similar and dissimilar materials.

Thiol-ene chemistry is a emerging and environmentally friendly polymer synthesis. It is therefor obvious that new applications would be sought for the process. Currently, the use of Thiol-ene chemistry is being investigated for use as a replacement chemistry for nail polish. However, a nail polish formulation requires a consistent and aesthetically pleasing application of colorant. Our project looks at the application of colorants to Thiol-ene coatings.

Expandable polymeric microspheres as stretch film components were investigated for pallet wrap applications. Advantages of this novel technology may include reduced fossil-fuel based plastics, solid waste, film density, and weight. Multilayer stretch wrap samples containing microspheres were produced on a stretch film processing line. Optical microscopy showed that the microspheres were intact and expanded 3-5X. Overall, testing showed that tensile, modulus, water vapor barrier, and cling were decreased by the addition of microspheres.

The increasing social pressure for biodegradability, environmentally?friendly products, and sustainable products for developing countries has launched the use of natural fibers in fiber reinforced polymer composites. Due to the integration of organic material in thermoplastics, the fiber?matrix interfacial bonding is quite poor. While the organic material is hydrophilic, able to absorb water, the majority of polymer matrices are hydrophobic, unable to bond with water. The interfacial shear strength, a quantity to measure this bonding, has been shown to be improved through morphological and chemical treatment. In this context, the interfacial shear strength of banana fiber in low?density polyethylene has not been fully characterized. The aim of this study is to analyze and improve the interfacial shear strength of banana fiber in a polymer matrix through a variety of surface treatment and modification techniques. For characterization of the fiber?matrix interfacial bonding, a commonly used micromechanical technique, the pull?out test, is used.

This experiment determined the most effective technique in crosslinking HDPE to replace PP medical containers. HDPE was crosslinked using silane methods at levels of 2%, 5%, and 10% and irradiation at levels of 21.6kGy, 42.12kGy, and 105.3kGy. After crosslinking, these materials, along with a medical grade PP and a general grade of PE were tested using melt index, stress relaxation, tensile, impact, flexural, HDT, and autoclave sterilization. The e-beam at 21.6kGy yielded the results closest to the PP.

Hollow Glass Microspheres, due to their unique spherical geometry and low density, provide several benefits in glass fiber reinforced composites. They help produce lighter weight parts in order to achieve stringent fuel economy targets for automotive and aerospace manufacturers. They also provide productivity benefits through shorter cooling times, enhanced dimensional stability and less warpage – helping to reduce waste and improve throughput. This paper demonstrates these benefits with effective formulation strategies in glass fiber filled polypropylene and polyamides.

Biobased and biodegradable ternary blends from poly (lactic acid) (PLA), poly(3-hydroxybutyrate-co- hydroxy-valerate) (PHBV), and poly(propylene carbonate) (PPC) were melt-compounded using a K-mixer and fabricated using an injection molding machine. The miscibility, degree of crystallinity, thermal stability, and mechanical properties were investigated. The blends were observed to be immiscible. PPC provided greater thermal stability in the blends compared to PHBV. The toughness and strain-at-break of the ternary blends were far superior to that of the binary blends due to the synergistic effect of the dispersed components. The stiffness and strength of the blends were consistent with those of the PLA matrix. The existing micromechanical models fit well for stiffness but under-estimated the tensile strength. As such, a new empirical model was developed that took into consideration the flexibility that exists between the immiscible blends.

Bioplastic sheets made from plasticized meat and bone meal (MBM) protein have high water vapor permeability (WVP) and low mechanical properties that are further affected by environmental humidity. This paper describes the improvement of tensile properties and moisture resistance of the sheets by two routes: (i) chemical crosslinking of the protein with calcium ions and (ii) blending with a synthetic polyethylene. The calcium ions led to a rigid glassy state of the modified MBM with 4 and 6 times higher tensile strength and modulus, respectively, but no significant improvement in WVP. Blending of polyethylene with MBM significantly improved moisture resistance and tensile properties.

This work is concerned with the determination of changes in molar masses of virgin and recycled PET resulting from the action of a chain extender additive compounded in a laboratory internal mixer, based on the processing data provided by the mixer, without further analysis. Results obtained show that the additive increases the molecular weight of both, virgin and recycled PET. Actual values depend on the amount of additive used and processing conditions. The additive tested is more efficient increasing the molar mass of the virgin versus the recycled resin (more additive is needed to obtain the same relative increase).

Polyphenylene Ether (PPE) is an engineering thermoplastic resin usually blended with polystyrene (PS) [crystal polystyrene (CCPS) and or High Impact Polystyrene (HIPS)] to improve properties including the processability. The overall performance of the resulting Noryl™ resin is highly dependent on the quality of the PS. This study presents some of the challenges involved in qualifying open loop PCR PS and key factors that could have affected their performance due to the recycle history and contaminations of the raw material compared to the virgin PS. PCR HIPS properties were simulated by recycling & spiking virgin HIPS with the contaminations.

Filler reinforced thermoplastics especially for natural filler reinforced plastics have been frequently used to improve the physical and thermal properties of polymer materials in plastic industry due to their low density, low cost and environmental friendliness. At current study, a preliminary investigation on the mechanical properties and morphologies of polypropylene (PP) reinforced by wood powder were carried out. Two different compounding screws with different mixing sections were used to evaluate the effect of compounding screw geometry on the appearance and mechanical properties of cellulose/PP composites since the screw section geometry has an effect on the final mixing condition of filler/matrix, filler damage and scorch. Additionally, the effect of wood particle size on the mechanical properties of wood/PP composites was also evaluated based on the tensile and Izod impact tests. The reflection-type optical microscope and scanning electron microscope (SEM) observation on the specimen surfaces were used to discuss the powder distribution degrees and interface properties.

Rice husk is a major biomass that is abundant, renewable and thus is promising material for the development of biodegradable polymers. The physical structure of rice husks between two different varieties of long grain rice has been evaluated in this study. The results show that the wall of the rice husk consists of 3 different layers with full and hollow fibers with different orientations. The fibers consist predominantly of cellulose and hemicellulose. Rice husk also contains about 10% moisture and about 20- 25% silica. The different varieties of rice husk have a similar structure, but different thicknesses of various layer and different diameters for the fibers. Silica is concentrated mostly in the outer layer and is the main reason why rice husks need to be modified before they can be used to develop biodegradable polymers or employed as reinforcing agents in other polymers.

The use of elastomer components in technical fields is enormously increasing. Elastomers can be used in a wide spectrum of applications including automotive-, machin-ery- and plant engineering, as well as in marine and civil engineering areas. Due to their properties regarding form-ability, workability, flexibility and adhesion, also the research activities are increasingly rising. In particular, the exploration of the aging behavior of polymers is getting more and more attention. With respect to literature, only a few experimental studies are dealing with the aging behavior of elastomers. Experience has shown that the properties of rubber materials can change significantly over time. The field of chemical aging is of particular importance due to the changes of the molecular structure and the cross-linking of the material during the aging process. These changes may in fluence a variety of properties such as weight, tensile and flexural strength. For more accurate predictions regarding the life time of an elastomeric component, all environmental factors need to be thoroughly experimentally investigated. In the light of these statements, more research activities concerning the long-term behavior of elastomers are nec- essary. This is the point where the present contribution attaches. We investigate natural rubber under different environmen-tal conditions. Therefore, we use air, seawater, distilled water, freshwater and salt solutions of 6%, 12% and 24%. The elastomer specimensare exposed to the medium and then aged by using different isothermal temperatures of 23°C, 60°C and 80°C. At predetermined aging times the samples are taken out of the medium and are experimen-tally investigated. Therefore, mechanical, calorimetrical and optical experiments are performed. The evaluated data is pointing out that the material is changing its properties during the aging time. Both soften-ing and stiffening effects can be observed relating to the environmental condition.