SPE Library

Polypropylene (PP)-based sandwich injection moldings with biodegradable polymers in the core were carried out. A compatibilizing agent and high flow PP were used as modifiers to improve interfacial adhesion between the skin and the core. In order to investigate the interfacial strength between the skin and the core, 180o peel test was conducted whereby the skin was peeled from the core. It was found that the interfacial strength between skin and core was improved by incorporation of modifiers, whose functions were understood by the morphological observation. From the combination of sandwich molding and polymer alloying technologies of this study, the possibility was derived to make products composed of PP and biodegradable polymer.

Polyolefins are utilized frequently in durable products that call for extended life in a variety of environmental conditions. Many of these products require color and almost all require and enhanced degree of resistance to the stresses of an exterior environment. The selection of plastic colorants that can withstand harsh environmental conditions is critical to ensuring the long term appearance of a polyolefin based durable product. Likewise, the correct choice of plastic additives for exterior applications must be made in order to ensure acceptable product appearance and performance over time.This paper examines key design considerations for durable polyolefin products in terms of additive selection. Special consideration is made in terms of selecting colorants that are considered non-toxic. A practical example is presented.

Reinforced thermoplastic matrix pipes may be subjected to different types of loading conditions as well as different environmental conditions. However, they may suffer damage due to unexpected working conditions (low velocity impact, such as stones, tools, etc). This paper describes a methodology based upon fracture mechanics to evaluate possible pipe damages. It reports a set of tests made to characterize materials and pipes. Fracture Mechanics tests were made in samples subjected to low velocity impact. The study of damage evolution was done by using the ESPI (Electronic Speckle Pattern Interferometry) technique in order to determine the delamination area.

Well-dispersed biodegradable and bio-based blends and nanocomposites have been successfully created by solid-state shear pulverization. Pulverization of granular starch and polyethylene (PE) resulted in damaged starch granules. This altered granule morphology led to improved oxygen barrier properties and tensile modulus in PE/starch blends. High levels of dispersion were also achieved in polymer/clay nanocomposites using poly(caprolactone) as the matrix. Varying levels of clay exfoliation were achieved by altering processing conditions during pulverization. These materials also had improved barrier properties.

A chemical recycling process was used to synthesize ?- and ?,?-(metal carboxylate) poly(lactic acid) (PLA) ionomers. Telechelic PLAs containing carboxylic acid groups, which were neutralized with appropriate metal acetates to produce Na-, Li-, K-, Zn-, Ca- and Y-?- and ?,?-telechelic PLA ionomers. Functionalization of the PLA was confirmed by FT-IR and 1H-NMR. In general, the Tg and Tm of the ionomers increased with molecular weight (which also lowered the ion-concentration) and ionization of the carboxylic acid. For a fixed molecular weight, the increase in Tg and Tm were linearly dependent on the ratio of q/a, where q is the cation charge and a is its ionic radius. Crystallization behavior was dependent on the ion concentration and location of the metal ions. The presence of the ionic groups increased the modulus of the polymer and the largest changes were observed with multivalent cations. The ?-(Y carboxylate) PLA even displayed a rubber-like plateau in its softening behavior.

Containers and packaging represent 32% of solid waste in the USA. Around 65% of this amount is derived from biobased materials such as paper, paperboard and wood, and the rest is composed of glass, metal and plastic. Glass and metal are abundant. Plastics in contrast are mainly obtained from scarce petroleum resources. Therefore, there is much interest in the production of biopolymers obtained from biobased resources, which are forecasted to reduce petroleum dependence. This article provides an overview of the current development and use of biopolymers in packaging applications, and examines their sustainability. It presents a cradle to cradle analysis and the current regulation of these materials.

As a sustainable alternative to petrochemical-derived products, poly(lactic acid) (PLA) is gaining a lot of interest in recent years. PLA has good optical clarity and high stiffness, but it is also intrinsically brittle. In this paper, the comparison between a specially engineered high aspect ratio mineral-EMforceTM Bio calcium carbonate, mica and talc in reinforcing PLA was performed. It was found that EMforceTM Bio calcium carbonate was extremely effective in improving the low temperature impact toughness as well as increasing the stiffness of PLA. Further the addition of EMforceTM Bio calcium carbonate to PLA does not hinder its compostability at elevated temperatures.

Digital inkjet printing has escaped the traditional confines of the graphic arts market and exploded into the realm of industrial applications. UV curable inkjet inks are enjoying the fastest growth due to their instantaneous cure, excellent jetting, and green" attributes. The industrial possibilities are limitless and each application requires a specific ink formulation to meet precise requirements. The inks must demonstrate robust characteristics including high flexibility and elongation abrasion resistance adhesion to a myriad of substrates including metals low surface energy plastics glass and ceramics as well as excellent lightfastness and rapid curing. This paper explores the challenges that a formulator encounters while pursuing industrial opportunities and offers suggestions to create inks that are a perfect match for each application."

The integrity performance and service time of certain automotive subsystems is adversely affected by moisture ingress into contained environments. Corrosion of air conditioning (AC) system components caused by moisture initially present in the refrigerant and moisture permeated through the seals during the AC unit service life is one example. Another one is water vapor condensation in optical components used for night and rear vision systems as well as optical proximity sensors often causing their malfunction in changing environmental temperature and humidity conditions. Desiccating multiforms attached to a condenser coil have long been used in automotive AC units to absorb the residual moisture and the moisture permeating from outside. The new direction in AC moisture control is the use of sorbent-loaded polymer composites in AC structural parts that eliminate the need for individual desiccating multiforms their assembly operation as well as the associated noise from the assembly. Desiccating composite enclosures and seal materials are simultaneously targeted for improving performance of optical components. Volatile organic compound (VOC) emissions from fuel tanks and lines into atmosphere can also be reduced by using VOC absorbing composite materials as reactive barriers to permeation in fuel tank and supply line design. The performance of sorbent-loaded composites is evaluated from the standpoint of two distinct design targets: removal the target vapor from the contained environment and reducing the rate of ingress from the external environment. The concepts of the layer reactivity the adsorptive capacity and the sorption rate are applied to the homogeneously reactive media and the sorbent-loaded polymer composites. The corresponding differences in performance and design requirements are discussed.

Polylactide (PLA) is a biodegradable compostable thermoplastic polymer produced from corn an annually renewable resource. In moving towards developing a sustainable vehicle use of materials such as PLA could greatly contribute to the goal of a more environmentally friendly vehicle. To date several non-automotive applications of PLA have been commercialized. These include PLA fiber/textile applications for clothing carpeting and linens; as well as blow molded articles for food packaging. Thus far for automotive use a single niche application of compression molded PLA has been developed. Here we seek to optimize the injection molding process conditions and composition of PLA composites for automotive interior applications. The effects of adding various reinforcements to the PLA resin for property improvements were assessed. Crystallinity modulus and strength properties were evaluated by differential scanning calorimetry (DSC) tensile and flexuarl testing.

The use of renewable materials in commercial products has gained attention over the past several years. Biomaterials can offer significant advantages over conventional materials such as: sustainability reduction of petroleum dependence lighter weight of components and potential lower cost. In our studies we demonstrate the use of soy-derived materials in two primary thermoset applications: sheet molding compounds (SMC) and polyurethane foam. SMC composites were produced using soy resin in place of a portion of the vinyl ester resin to evaluate mechanical performance process capabilities and component performance. In addition composite reinforcements of continuous hemp fiber non-woven hemp mats fiberglass and hybrids (fiberglass/continuous hemp twine mixtures) were examined. Results indicate that the soy resin composites demonstrate equivalent properties to those of the vinyl ester resin composites and are equally able to be molded in to complex geometries. While substitution of glass reinforcement with natural fibers was found to reduce the mechanical performance of the composites hybrid composites of glass and hemp fibers provided promising results. Hydroxylized soy oil has also been used as a polyol in flexible polyurethane foam formulations. Foam formulations have been optimized for mechanical and processing performance. One of the key technical challenges of soy foams are their inherent odor. Two odor reduction methods will be discussed including a novel low odor method to functionalize soybean oil.

In this work natural fiber and wood composites based on neat and recycled polypropylene (PP) were fabricated by melt processing. Different formulations including various reinforcement content different types of coupling agents different types of reactive additives and an impact modifier were developed. The reinforcements were in the form of natural fibers like banana flax rice husk and palm fibers and of wood sawdust. For the long fiber composite systems processing was done by compression molding of piles of long fiber mat and extruded polypropylene film. For the short fiber composite the samples were prepared by extrusion followed by injection molding. The tensile flexural and impact performance were characterized and all composites show superior mechanical properties when compared with the pristine matrix. Mechanical performance of the wood composites was also evaluated before and after conditioning in water for 1 and 7 days. Results indicate that the composites resist to humidity very well. The results also demonstrate the effect of formulations on the performance of the recycled composites.

Heritage Bag Company has developed compostable bags and liners, which are produced from composites utilizing polymer and mineral materials technology of Heritage Plastics, Inc. This product line is based on proprietary blends of different biodegradable polymers which have been modified using mineral reinforcement technology to produce a readily extrudable polymer composite. This modification yields polymer processing, end-use products such as film and bags with characteristics very similar those obtained with higher-alpha olefin LLDPE resins, yet meet the requirements of ASTM D 6400-99.

This paper presents the application of recycled industrial HDPE and PP and their blends with virgin resins in pail design using finite element analysis. Results predict that these blends can be used in pails for the packaging of non food grade materials such as paints, oil and grease.

Abbreviated terms are routinely employed in the plastics industry in generic marking of molding products to assist in identification of the plastics for separation in recycling besides in trade and technical literatures. Existing ISO, ASTM and other standards provide clear guidelines for abbreviated terms for polymer families. In practice, however, a wide range of inconsistent abbreviated terms are quite common in the industry. This has significant implications for the general consumers as well as those involved with plastics recycling. The challenge is to arrive at uniform globally acceptable single set of abbreviated terms in order to addressing this issue.

Polypropylene (PP) and polysulfone (PSU) have not been previously blended due to viscosity and processing temperature variations. These blends made using an environmentally-friendly process showed structureproperty improvements with the addition of functional polyolefins.

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.

In Mexico and other countries of Latin America, the per capita consumption of plastics has more than doubled during the last decade. This results in the increased generation of plastic residues which leads to the growing plastics waste disposal problem. This paper presents a concept of Eco-plastics" which is an integrated approach to solving plastic waste generation challenges in Latin America. A feasibility study is recommended as a first step towards the implementation of this concept."

E-glass fiber-reinforced vinyl ester plastics with up to 5 wt% montmorillonite dispersed in the matrix were immersed in distilled water for nine weeks. At one week intervals, samples were removed and sectioned, both perpendicular and parallel to the fiber direction. Scanning electron microscopy revealed progressive degradation of the matrix and the glass reinforcement. However, the rate of moisture attack decreased with increasing amount of dispersed clay; this was confirmed by strength, stiffness and ductility measurements.

An unintended consequence of the growing consumption of plastics is the increase in amount of plastics products discarded daily by consumers worldwide contributing to growing share of plastics in municipal waste streams. With the product life cycle of most products getting shorter each day, product designers have a responsibility to minimize the negative impacts of their designs on the environment. This paper describes best practices for incorporating environmental impact considerations during various stages of plastics product development, and provides specific guidelines to assist designers for eco-design of plastics products.