The following literature review has been originally conducted as part of the Waste plastic extruder for Mech 461. It now supports the Recyclebot project. Please add content.

## Polymer Properties Table

Density (g/cc) Hardness Tensile Strength, Yield (MPa) Elongation at Yield (%) Modulus of Elasticity (GPa) Flexural Modulus (GPa) Processing Temperature (˚C) Middle Barrel Temperature (˚C) Die Temperature (˚C) .935 – 1.01 57.0 – 73.0 Shore D 15.2 – 42.1 6.00 – 13.00 .700 – 2.62 .586 – 2.62 160 – 260 n/a 175 – 190 .916 - .944 51.0 – 58.0 Shore D 7.58 – 17.9 n/a n/a .276 - .480 n/a n/a n/a .915 - .939 42.0 – 57.0 Shore D 7.60 – 12.0 n/a .152 - .290 .0800 - .276 108 – 340 177 - 210 204 – 221 1.03 – 1.17 68.0 – 113 Rockwell R 13.0 – 65.0 .620 – 30.0 1.00 – 2.65 1.20 – 5.50 180 – 274 190 – 250 210 -250 .886 – 1.84 57.0 -120 Rockwell R n/a 1.60 – 30.0 .680 – 2.60 .620 – 2.55 120 – 330 190 -280 200 -310 1.20 – 1.26 120 – 126 Rockwell R 58.6 – 70.0 6.00 – 50.0 1.79 – 3.24 2.09 – 3.10 270 – 343 250 – 332 n/a 1.25 – 1.91 80.0 – 95.0 53.0 – 265 3.5 – 30.0 1.83 – 5.20 1.90 – 15.2 120 – 295 n/a n/a

all data from Matweb Material Property Data

## Searches

• Waste plastic extrusion
• RepRap
• Fab@home
• Open Source Rapid Prototyping
• Thermoplastics
• Polylactic acid
• plastics waste developing world
• thermoplastics emissions

## Open Source Rapid Prototype Technology

### RepRap - the replicating rapid prototyper

Rhys Jones, Patrick Haufe, Edward Sells, Pejman Iravani, Vik Olliver, Chris Palmer and Adrian Bowyer, "RepRap - the replicating rapid prototyper", Robotica, 29(1), pp. 177 - 191 (2011).

Abstract:

This paper presents the results to date of the RepRap project – an ongoing project that has made and distributed freely a replicating rapid prototyper. We give the background reasoning that led to the invention of the machine, the selection of the processes that we and others have used to implement it, the designs of key parts of the machine and how these have evolved from their initial concepts and experiments, and estimates of the machine's reproductive success out in the world up to the time of writing (about 4500 machines in two and a half years).

Notes:

• brief history of self replication and definitions of associated terms.
• explains philosophy and motivations for the invention of the RepRap by Bowyer, as well as decision to go open source.
• step-by-step evolution of the RepRap from first model up to the RepRap Mendel.
• includes design process and detailed description of how the machine functions.
• Follow Up: Look into PLA production

A wealth of information is available at the RepRap wiki found here here. This wiki has detailed construction instructions and includes many improvement, add-ons, etc. from the open source community. Of particular interest to this project are the following two, which attempt to create feedstock from recycled plastic:

### Fab@Home - the personal desktop fabricator kit

E. Malone and H. Lipson, "Fab@Home: the personal desktop fabricator kit," Rapid Prototyping Journal, vol. 13, pp. 245-255, 2007.

Abstract:

Purpose – Solid freeform fabrication (SFF) has the potential to revolutionize manufacturing, even to allow individuals to invent, customize, and manufacture goods cost-effectively in their own homes. Commercial freeform fabrication systems – while successful in industrial settings – are costly, proprietary, and work with few, expensive, and proprietary materials, limiting the growth and advancement of the technology. The open-source Fab@Home Project has been created to promote SFF technology by placing it in the hands of hobbyists, inventors, and artists in a form which is simple, cheap, and without restrictions on experimentation. This paper aims to examine this.

Design/methodology/approach – A simple, low-cost, user modifiable freeform fabrication system has been designed, called the Fab@Home Model 1, and the designs, documentation, software, and source code have been published on a user-editable "wiki" web site under the open-source BSD License. Six systems have been built, and three of them given away to interested users in return for feedback on the system and contributions to the web site.

Findings – The Fab@Home Model 1 can build objects comprising multiple materials, with sub-millimeter-scale features, and overall dimensions larger than 20 cm. In its first six months of operation, the project has received more than 13 million web site hits, and media coverage by several international news and technology magazines, web sites, and programs. Model 1s are being used in a university engineering course, a Model 1 will be included in an exhibit on the history of plastics at the Science Museum London, UK, and kits can now be purchased commercially. Research limitations/implications – The ease of construction and operation of the Model 1 has not been well tested. The materials cost for construction (US$2,300) has prevented some interested people from building systems of their own. Practical implications – The energetic public response to the Fab@Home project confirms the broad appeal of personal freeform fabrication technology. The diversity of interests and desired applications expressed by the public suggests that the open-source approach to accelerating the expansion of SFF technology embodied in the Fab@Home project may well be successful. Originality/value – Fab@Home is unique in its goal of popularizing and advancing SFF technology for its own sake. The RepRap project in the UK predates Fab@Home, but aims to build machines which can make most of their own parts. The two projects are complementary in many respects, and fruitful exchanges of ideas and designs between them are expected. Notes: • less geared toward self replication than RepRap, but same goal of making rapid prototyping widely available. • uses syringe based extrusion versus the filament extrusion of RepRap • open source software works solely with Windows OS at time of publication. Additional Resources on Fab@Home: Check out the Fab@Home wiki [1]. This page includes detailed construction guidelines, as well as improvements, add-ons, etc. developed by the open source community. A few general notes: • Similar project to RepRap and RapMan. • Developed at Cornell University by Hod Lipson and Evan Malone. • Uses open source developed hardware and software. Software programs are have been specifically developed for the Fab@Home but are open source. • Extrusion uses a syringe/piston based system – can handle diverse materials. ### Rapid Prototype Manufacturing System A.Tan, T. Nixon, "Rapid Prototype Manufacturing System", Unpublished undergraduate paper, The University of Adelaide, Adelaide, Australia,(2007) Notes: • covers applications and benefits of small scale rapid prototyping technology. • summary of existing small scale and commercial technologies. Comprehensive review of process methods. (i.e. Fab@home uses solid freeform fabrication (SFF) while RepRap uses fused deposition method (FDM)). • information on rapid prototyping materials including good review of thermoplastics. • some testing of materials with Rapid Prototyper (properties include viscosity, cure time, layering time, flow rate). • develop alternative deposition system for Fab@Home. Seems to be successful granule extruder. • interesting idea - 2 heated sections, one for melting, the other to maintain desired temperature through nozzle. • incorporate heated hopper for pre-melting of material • screw extruder for material deposition. • some optimization completed. ### RapMan • commercially available, proprietary version of RepRap Darwin. • kits available retailing at approximately$1000.
• some proprietary components.

### MakerBot

• another open source 3D printer which is sub-\$1000.

## Plastics Recycling

### An Investigation of Mechanical, Thermal and Creep Behavior of Recycled Industrial Polyolefins

S. Haider Rizvi, S. H. Masood, Igor Sbarski. "An Investigation of Mechanical, Thermal and Creep Behavior of Recycled Industrial Polyolefins" Progress in Rubber, Plastics and Recycling Technology." 23(2), 97 - 110. 2007

Notes:

• recycling industrial plastics ex. plastic pails and containers
• polyolefins - PP, HDPE, most common is a mix of polyethylene and polypropylene
• blend - physical mixture of 2 or more polymers, goal = get desired properties, done by diluting engineering resins w. low cost commodity polymers
• as recycled percentage in HDPE increases --> decrease in tensile modulus, flexural modulus and lower yield pt shifted toward the lower strain, no changes in tensile and flexural strength, over 40% recycled - significant decrease in crystallinity
• as recycled percentage in PP increases --> tensile modulus decreased , flexural modulus increases slightly, no changes in tensile and flexural strength, until 60% recycled PP - crystallinity decreases linearly, past 60% no change in crystallinity
• Creep
• fast creep --> elastic deformation
• slow creep --> viscoelastic deformation (most of creep process), permanent deformation
• dependent upon temp and stress

### Recycling and Recovery Routes of Plastic Solid Waste (PSW): A review

""S.M. Al-Salem, J.Baeyens, P. Lettieri, "Recycling and Recovery Routes of Plastic Solid Waste (PSW): A review" Waste Management, 29(10), 2625-2643, 2009. doi:10.1016/j.wasman.2009.06.004""

Abstract:

Plastic solid waste (PSW) presents challenges and opportunities to societies regardless of their sustainability awareness and technological advances. In this paper, recent progress in the recycling and recovery of PSW is reviewed. A special emphasis is paid on waste generated from polyolefinic sources, which makes up a great percentage of our daily single-life cycle plastic products. The four routes of PSW treatment are detailed and discussed covering primary (re-extrusion), secondary (mechanical), tertiary (chemical) and quaternary (energy recovery) schemes and technologies. Primary recycling, which involves the re-introduction of clean scrap of single polymer to the extrusion cycle in order to produce products of the similar material, is commonly applied in the processing line itself but rarely applied among recyclers, as recycling materials rarely possess the required quality. The various waste products, consisting of either end-of-life or production (scrap) waste, are the feedstock of secondary techniques, thereby generally reduced in size to a more desirable shape and form, such as pellets, flakes or powders, depending on the source, shape and usability. Tertiary treatment schemes have contributed greatly to the recycling status of PSW in recent years. Advanced thermo-chemical treatment methods cover a wide range of technologies and produce either fuels or petrochemical feedstock. Nowadays, non-catalytic thermal cracking (thermolysis) is receiving renewed attention, due to the fact of added value on a crude oil barrel and its very valuable yielded products. But a fact remains that advanced thermo-chemical recycling of PSW (namely polyolefins) still lacks the proper design and kinetic background to target certain desired products and/or chemicals. Energy recovery was found to be an attainable solution to PSW in general and municipal solid waste (MSW) in particular. The amount of energy produced in kilns and reactors applied in this route is sufficiently investigated up to the point of operation, but not in terms of integration with either petrochemical or converting plants. Although primary and secondary recycling schemes are well established and widely applied, it is concluded that many of the PSW tertiary and quaternary treatment schemes appear to be robust and worthy of additional investigation.

Notes:

• re-extrusion (primary recycling) - reintroduction of scrap/industrial/single polymer plastic into exrusion cycle
• scrap must be semi-clean = unpopular w. recyclers
• process scrap - products made that don't meet standards of producer
• in UK process scrap = 250,000 tons --> 95% primary recycled
• recycling household waste challenges
• large # of sources supply small quantities of PSW
• resource drain, high operating costs

### Examination of the possibility of recycling and utilizing recycled polyethylele and polypropylene

Cemal Meran, Orkun Ozturk, and Mehmet Yuksel, Examination of the possibility of recycling and utilizing recycled polyethylele and polypropylene, Technical Report (Kinikli, Denizli, Turkey: Pamukkale University, Mechanical Engineering Department, n.d.).

• manufactured in the following percentages: 31% polyethylene (PE), 17% polyvinyl chloride (PVC), 15% thermosets, 14% polypropylene (PP), and 9% polysty- rene (PS)
• plastics best suited for recycling are PE, PP, PVC, and polyethylene terephthalate (PE)
• The recycled plastics should not be used in the medicine and food sec- tors. However, recycled plastics could be used in 90% of applications, such as in manufacturing contractile films, some kinds of pipe, sandwich structured laminates, and some containers targeted for industrial us
• results of the experiments demonstrated that the usability of the recycled low-density polyethylene, high- density polyethylene, and polypropylene is 100%
• polypropylene- tensile strength, even in bars pressed from the highly recycled polypropylene, decreased 15% compared with the pure material.
• HDPE 24% decrease
• LDPE 36% decrease

### Characterization and recovery of polymers from mobile phone scrap

Angela C Kasper, Andréa M Bernardes and Hugo M Veit. "Characterization and recovery of polymers from mobile phone scrap"

Waste Manag Res 2011 29: 714 originally published online 7 March 2011. DOI: 10.1177/0734242X10391528


Notes:

• users keep particular models of mobile phones for from 9 to 18 months before replacing them with newer or better equipment
• estimated that the global number of such obsolete mobile phones is now more than 500 million and is growing constantly
• In developing countries such as China and India, waste is 'processed' in backyards or small workshops using very primitive methods (burning in the open air or washing with acids) to recover only any metal of economic interest. Normally in these artisanal procedures, the polymers are lost and atmospheric pollution is inevitable.
• suitable industry-level mechanical processing emerges as a reasonable alternative where it can be arranged to concentrate the metals into one group and the polymers and ceramics in another
• 95% of the components were made from a blend of PC/ABS
• tensile strength of recycled material is similar to that of virgin material, and the density presented (1.08 g cm^3) is closer to the density of ABS, indicating a high content of ABS in the blend. The recycled material demonstrated greater hardness value than virgin material, probably due to the presence of inorganic elements in the blend. Table 4
Page data
Type Literature review Alexandra Glover, Christian Baechler 2011 CC-BY-SA-4.0 14,217 No main image Alexandra Glover, Christian Baechler (2011). "Waste plastic extruder: literature review". Appropedia. Retrieved August 18, 2022.
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