SPE Library
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.
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Recycling
Various topics related to sustainability in plastics, including bio-related, environmental issues, green, recycling, renewal, re-use and sustainability.
BENIGN PROCESSING OF HIGH PERFORMANCE POLYMERIC FOAMS OF POLY(ARYLENE ETHER SULFONE)
An environmentally benign process to produce high performance polymeric foams from poly(arylene ether sulfone) was developed. The high performance polymeric foams were produced by utilizing carbon dioxide and water as the physical blowing agents because they are plasticizers for the polymer. By controlling the vitrification of the poly(arylene ether sulfone) through the diffusion of the plasticizers and foaming temperature the cell size and foam density could be readily varied. The foam density varied between 15 to 85% of the unfoamedpolymer and cell sizes ranged between 1 to 200 ?¬m. Theaffect of the cell size and density on tensile properties will be discussed.
ENVIRONMENTAL STRESS CRACKING OF CPVC PIPE BY MIXED GLYCOLS
CPVC pipe is often used for containment of water in fire sprinkler systems, usually with glycerol as the antifreeze, but too often with ethylene or propylene glycol. Environmental stress cracking has caused much distress and economic damage. This test program shows that a mixture of these two glycols can be more damaging to CPVC pipe than either of the glycols by itself. Earlystage cracks are also illustrated, as observed by Scanning Electron Microscope at 1000X magnification.
ENVIRONMENTALLY SUSTAINABLE THERMOPLASTIC FOAMS: POLYLACTIDE FOAMS VERSUS POLYSTYRENE FOAMS
Polystyrene (PS) foams have a number of desirable properties and thereby have been used for many applications. However, one of the most notable drawbacks of PS foams is its non-biodegradability. In recent years, polylactide (PLA) has been viewed as an environmentally sustainable substitute of PS. In this context, this paper aims to provide head-to-head comparisons between PLA and PS foaming processes, in terms of the cell formation mechanisms and foamability of the resultant foams.
BIODEGRADABLE POLYURETHANE/SOY PROTEIN SHAPE-MEMORY POLYMER BLENDS PREPARED VIA ENVIRONMENTALLY-FRIENDLY AQUEOUS DISPERSIONS
Biodegradable and biocompatible shape-memory polymer blends of soy protein (SP) and polyurethane (PU) based on poly(?æ-caprolactone) (PCL) has been synthesized using environmentally-friendly aqueous dispersion technique. High-pressure supercritical carbon dioxide (scCO2) foaming technique was applied to the blends to generate three-dimensional interconnected porous structures or scaffolds with special enhanced benefits for potential biomedical applications such as soft tissue engineering and/or drug release. Blending PU dispersion (PUD) with SP significantly increased the biocompatibility and biodegradability properties of the materials and improved their shape-memory capability. The PCL soft segment was found to be miscible with SP over the entire range of concentration as confirmed by DSC measurements, where a single Tg located between the Tg of the pure SP and PCL soft segment was observed for all blend concentrations. The shape-memory behavior of the blends was investigated for different concentrations under free-stress condition. The rate of strain recovery was found to be SP concentration dependent. The stress recovery of the blend reached a maximum value at wSP = 0.1 weight fraction. This finding was attributed to the maximum increase in the degree of crystallinity of PCLsoft segment at wSP = 0.1 as conformed by X-ray analysis.
BIODEGRADATION OF POLY(HYDROXY BUTANOIC ACID) COPOLYMER MULCH FILMS IN SOIL
Agricultural mulch films that are used to cover soil of crop rows contribute to earlier maturation of crops and higher yield. Incineration and landfill disposals are the most common means of disposal of the incumbent polyethylene mulch films; these are not environmentally friendly options. Biodegradable mulch films that can be rototilled into the soil after crop harvest are a promising alternative to offset problems such as landfill disposal, and film retrieval and disposal costs. In this study, an in-house laboratory scale test method has been developed in which the rate of disintegration, as a result of biodegradation, of films based on polyhydroxybutanoic acid (PHB) copolymers were investigated in a soil environment using residual weight loss method. The influence of soil composition, moisture levels in the soil and industry-standard anti-microbial additive in the film composition on the rate of disintegration of PHB copolymer films will be discussed.
HOW NUCLEATED MMW HDPE RESINS INFLUENCE BARRIER FILM STRUCTURE DESIGN
This paper describes a film structure study involving nucleated medium molecular weight high density polyethylene (MMW HDPE) materials that enhance film properties. Using these new nucleated MMW HDPEs, several film structures have been designed to improve moisture barrier, oxygen barrier, toughness and cost, as well as reduce the environmental footprint by downgauging existing film structures. The films in this study use a variety of polyethylene materials commonly used in the film converting industry.
IMPROVEMENT OF INTRINSIC VISCOSITY OF RECYCLED PET BY RADIO FREQUENCY HEATING
The improvement of Intrinsic Viscosity of recycled poly(ethylene terephthalate)(R-PET) pellets by an industrial radio frequency(RF) heating is described. RPET pellets are made from post-consumer PET bottles, degraded by hydrolysis during distribution process. Hence, intrinsic viscosity(IV) or molecular weight of RPET exhibits significant lower compared to virgin PET, caused from cleavages of chains. This study indicates thermal recycling method of solid phase polymerization to improve the IV values, namely molecular weight of RPET pellets.
IMPROVEMENT OF INTRINSIC VISCOSITY OF RECYCLED PET BY RADIO FREQUENCY HEATING
The improvement of Intrinsic Viscosity of recycled poly(ethylene terephthalate)(R-PET) pellets by an industrial radio frequency(RF) heating is described. RPET pellets are made from post-consumer PET bottles, degraded by hydrolysis during distribution process. Hence, intrinsic viscosity(IV) or molecular weight of RPET exhibits significant lower compared to virgin PET, caused from cleavages of chains. This study evaluates the feasibility of RF Heat Treatment to improve the intrinsic viscosity of the material.
IMPROVEMENT OF INTRINSIC VISCOSITY OF RECYCLED PET
BY RADIO FREQUENCY HEATING
The improvement of Intrinsic Viscosity of recycled
poly(ethylene terephthalate)(R-PET) pellets by an
industrial radio frequency(RF) heating is described. RPET
pellets are made from post-consumer PET bottles
degraded by hydrolysis during distribution process.
Hence intrinsic viscosity(IV) or molecular weight of RPET
exhibits significant lower compared to virgin PET
caused from cleavages of chains. This study evaluates the
feasibility of RF Heat Treatment to improve the intrinsic
viscosity of the material.
CHARACTERIZATION OF THE MICROSTRUCTURE OF POLY (HYDROXY BUTANOIC ACID) COPOLYMERS DURING THEIR POST-FABRICATION ANNEALING AT ROOM TEMPERATURE
The mechanical properties of bio-based, biodegradable poly (hydroxy butanoic acid) or PHB copolymers are known to change considerably over a period of time after their parts are fabricated. This study will focus on the changes in semi-crystalline morphology during this aging process. The semi-crystalline morphology is characterized using the three-phase model (crystalline, mobile amorphous and rigid amorphous phases) and through a variety of experimental probes including thermal analysis, refractometry, x-ray diffraction and solid-state NMR.
CHARACTERIZING CO-CONTINUOUS MORPHOLOGY DEVELOPMENT IN MISCIBLE POLYLACTIC ACID / POLYVINYL ALCOHOL BIODEGRADABLE BLENDS
Targeted for tissue engineering scaffold applications, biodegradable polylactic acid (PLA) and water-soluble polyvinyl alcohol (PVA) resins were employed to produce miscible blends by means of melt blending in a thermokinetic mixer (K-mixer). Different volume fractions of PLA and PVA were melt mixed. After water leaching (extraction) of the sacrificial PVA domains, co-continuous morphology development of the blend systems was investigated via scanning electron microscopy (SEM). The dimensions of the voids occupied by PVA in the blends were measured using an image analysis tool. In addition, the miscibility of these blends was evaluated by thermal characteristic measurements using a differential scanning calorimeter (DSC). It was shown that the continuity development and microstructure features of PLA/PVA blends were dependent on the component composition and the miscibility.
INTERACTION OF HALS AND COLORANTS: PART II
A series of colorants including yellows, reds, blues and greens have been evaluated when processed with monomeric and oligomeric HALS in PP and HDPE. Comparisons have been done in masstone and tint looking at effects on color shift and strength.
CLOSED LOOP QUALITY CONTROL OF THE PROCESSING OF UNDRIED POLYCONDENSATES USING MELT DEGASSING SINGLE SCREW EXTRUSION
Processing undried polycondensates as PET or PA using a melt degassing single screw extruder is a real alternative to the conventional energy- time- and cost-consuming pre-drying process. Due to the industrial demand of processing recycled and low priced materials the moisture content or/and the resin mixture can substantially vary from batch to batch. This leads to a deviant molecular weight degradation and an unsteady final product quality. The paper presents an approach to compensate these variations in the feedstock in a closed-loop control. It is based on the direct influence of the degassing pressure on the moisture evaporation of the melt. The product quality is estimated online in the extrusion process e.g. via melt viscosity and is controlled by the degassing pressure in the extruder.
CLOSED LOOP QUALITY CONTROL OF THE PROCESSING OF UNDRIED POLYCONDENSATES USING MELT DEGASSING SINGLE SCREW EXTRUSION
Processing undried polycondensates as PET or PA using a melt degassing single screw extruder is a real alternative to the conventional energy-, time- and cost-consuming pre-drying process. Due to the industrial demand of processing recycled and low priced materials, the moisture content or/and the resin mixture can substantially vary from batch to batch. This leads to a deviant molecular weight degradation and an unsteady final product quality. The paper presents an approach to compensate these variations in the feedstock in a closed-loop control. It is based on the direct influence of the degassing pressure on the moisture evaporation of the melt. The product quality is estimated online in the extrusion process, e.g. via melt viscosity, and is controlled by the degassing pressure in the extruder.
COMPARISON STUDY OF N2 AND CO2 AS PHYSICAL BLOWING AGENTS FOR INJECTION FOAM MOLDED WOOD-FIBER PLASTIC COMPOSITE
Due to rising environmental concerns, the plastic
industry has been seeking bio-plastics that can replace
current plastics. Efforts are continuously being made to
reduce weight and cost without a major compromise to
required properties. Foaming can offer a plastic with
significant weight reduction. There has been research to
evaluate the effects of chemical blowing agents (CBAs)
on wood-fiber plastic composites (WPC). Although
physical blowing agents (PBAs) have a number of
advantages, their effects on WPC have not been fully
investigated. Therefore, this research utilizes N2 and CO2
to analyze their effects on the foaming and mechanical
properties of injection foam molded WPCs.
COMPLIMENTARY FAILURE ANALYSIS METHODS AND THEIR APPLICATION TO PLASTIC PIPE
A variety of methods can be employed to characterize failure modes of plastics and identify contributing factors. By combining visual and microscopic examination with chemical analysis, the reasons for ductile, brittle, or progressive failure may be determined. This paper provides a comparative analysis based on fractography and spectroscopic analysis of chlorinated polyvinyl chloride (CPVC) pipe samples that failed due to chemical exposure. Chemical degradation and environmental stress cracking failure modes are explored using optical microscopy, scanning electron microscopy, and FTIR.
MECHANICAL PROPERTIES OF HEAT-SEALED PART IN ENVIRONMENT-FRIENDLY FILM
Multi-layered laminated films are widely used as general packaging materials and thermal lamination is one of the environmentally friendly techniques since it does not involve solvents during lamination. The heat exerted during the heat- sealing process, however, could affect the lamination strength of these films. In this study, we focused on the relationship between the results of pinhole test and the properties of heat sealed parts.
MECHANICAL PROPERTIES OF HEAT-SEALED PART IN ENVIRONMENTFRIENDLY
FILM
Multi-layered laminated films are widely used as
general packaging materials and thermal lamination is
one of the environmentally friendly techniques since it
does not involve solvents during lamination. The heat
exerted during the heat- sealing process however
could affect the lamination strength of these films. In
this study we focused on the relationship between the
results of pinhole test and the properties of heat sealed
parts.
CORN (SUGARS) BASED CHEMISTRIES FOR THE POLYMER INDUSTRY
Corn (sugars) may be viewed as a chemical
feedstock to produce new monomers
polymers and additives for a broad range of
chemical intensive industries. Corn based
chemicals are attractive because they as
generally regarded as safe (GRAS) are a
renewable resource and can be made readily
available at competitive pricing. Interest is
focused on isosorbide which offers
molecular geometry and chemical
functionality compatible with many existing
commercial chemistries. Applications
ranging from the creation of new polymer
backbones for use as thermoplastics or
thermosets to the identification of low molar
mass compounds that can act as plasticizers
stabilizers or compatiblizers are under
investigation. Of special interest is the
impact of asymmetric reactivity chirality
and controlled stereochemistry in the design
and performance of new cost-effective
structures with commercial potential. As
petroleum becomes more expensive and the
assurance of long range cost-effective
supply questionable creation of alternative
chemistries from renewable resources such a
corn (glucose) becomes more attractive.
CORN (SUGARS) BASED POLYMER CHEMISTRIES FOR THE POLYMER AND COSMETICS INDUSTRIES
Corn (sugars) may be viewed as a chemical feedstock to produce new monomers, polymers and additives for a broad range of chemical intensive industries. Corn based chemicals are attractive because they as generally regarded as safe (GRAS), are a renewable resource and can be made readily available at competitive pricing. Interest is focused on isosorbide which offers molecular geometry and chemical functionality compatible with many existing commercial chemistries. Applications ranging from the creation of new polymer backbones for use as thermoplastics or thermosets to the identification of low molar mass compounds that can act as plasticizers, stabilizers or compatiblizers are under investigation. Of special interest is the impact of asymmetric reactivity, chirality and controlled stereochemistry in the design and performance of new, cost-effective structures with commercial potential. As petroleum becomes more expensive and the assurance of long range, cost-effective supply questionable, creation of alternative chemistries from renewable resources such a corn (glucose) becomes more attractive.
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