MONTHLY MEETING

For over 40 years, Zeus has grown to be a leader in the development and production of high-performance fluoropolymer tubing, as well as providing innovation in post-production finishing and strategic supply initiatives. Zeus produces tubing that delivers the temperature resistance, lubricity, high tensile strength, and exceptionally tight tolerances demanded by today's challenging applications in the medical, fluid handling, electrical and mechanical industry markets.

Headquartered in Orangeburg, S.C., Zeus operates multiple facilities in North America and internationally that guarantee a stable source of supply to customers anywhere in the world.

After spending ten years working in the polymer extrusion industry as an extruder operator and manager, Frank P. Tourville, Sr. branched off to found his own company – Zeus – in 1966. Over time, Zeus has grown from a small start-up into a world leader in high-performance polymer extrusions and a pioneering solutions provider. Zeus now operates 10 facilities on seven campuses worldwide in the United States, Ireland, and China..
 
 

Thursday May 21, 2009	Exponent Inc.	149 Commonwealth Drive, Menlo Park, CA 94025
Time:	NOON to 1:30 PM	You must RSVP on or before May 15, 2009
Cost:	$10 for lunch	LIMIT: 30 PEOPLE !! RSVP NOW
Contact:	Mikki Larner	RSVP  to mikki@plasmatechsystems.com

Directions to Exponent:

From the South (San Jose)
Take Bayshore Highway (101) North
Exit Marsh Road [84]
Proceed East toward Bayfront Highway [84]
Turn RIGHT on Independence Drive and at its end, RIGHT on Chrysler Drive
Chrysler Drive becomes Commonwealth Drive [parallel to 101]
Proceed to 149 on the LEFT.

From the North (e.g., SFO, San Mateo Bridge)
Take Bayshore Highway (101) South
Exit Marsh Road [84]
Proceed East toward Bayfront Highway [84]
Just after crossing over [101], turn RIGHT on Independence Drive and at its end, RIGHT on Chrysler Drive
Chrysler Drive becomes Commonwealth Drive [parallel to 101]
Proceed to 149 on the LEFT.

Dear SPE GGS members

Our last event with Brian Glasbrenner of Nature Works was very popular. We had 28 attendees. My hope is every event could be attended with such interest.  As such, I would like to request your input as to the topics you want to see SPE GGS sponsor and invite speakers discuss.  Obviously biodegradable polymers are a big deal today and will continue to demand considerable attention.  And, we will continue to bring more speakers with this kind of background in the future. However, I would like to offer all our members an opportunity to participate in the SPE GGS community and get something valuable out of your membership.  So, if you have a particular topic in mind that would be of interest, please contact me directly or one of our board members.

The presentation with Dr. Davis with Zeus is looking to be equally popular.  He will be speaking on their core competencies of biosorbable polymers and micro extrusion fluidic tubing.  While biological applications are their specialty, they have also worked with electronic devices, given there are similar high requirements for material performance.

Finally, SPE GGS is nearing the beginning of an election term for all our directors.  Several of our directors have been holding down the fort for while and we would really like to get new members willing to participate in SPE GGS and take over those responsibilities.  ALL board positions are open.  The positions of Treasurer and Spearhead Editor especially have seen Zia Shariat and Mike LoDico at the helm for some time and new leadership there would be very welcome.  You can nominate yourself or other person to any of the board positions.

Also, I will be creating a chair position with the responsibility of managing the upcoming SPE GGS LinkedIn group.  Yes, we are catching up to technology.  I hope this group can allow better networking within our section and serve as a forum for open discussion and postings for all topics polymer. The Chair would be responsible to maintain the group on LinkedIn and monitor the postings and manage discussions when needed.

Serving on the SPE GGS board of directors has several benefits 1) you get visibility in the SPE and plastics community 2) you have direct input into the speakers and topics we select 3) you are helping to advance polymer education and interests 4) you are helping our plastics community to be technically strong and up to date with current trends in the industry.  So, if you have the inclination to be a board member or would like to nominate someone, please contact me.  Elections will take place at the end of May.

Regards,

Alfonso Lopez
SPE GGS President
alfonso.lopez@hexcel.com

The GGS would like to thank those who attended the NatureWorks talk. The turnout was one of our best in recent times. The GGS is always appreciative of the effort made by those who attend our luncheons. Please remember to RSVP early for all our events and we do hope to see you again at our next event.

As we enter the new year, the GGS would like to schedule more hosted company profile events. Check back often in the CALENDAR SECTION of our web site for more details. In June our speaker is from Sefar Woven Fabrics. The GGS hopes you will join us for these events.

Tech Tip May 2009

PART DESIGN

Design the next step or was it to be the First step!

If we use all that has been discussed to date on the design of a part, the next step is to get a tool built. This is where the design check list and all parties need to set down and discuss. There have been many names associated with this step, concurrent design; upfront engineering and what may be called thinking for manufacturing. All basically want to take the part that has been designed and make sure it is designed for manufacturing at the best possible way, price, and economies.

1- Can we simplify the part design? Are there complex surfaces in the part that may be eliminated thus saving on tooling cost? Can we eliminate side actions in the tool with shut-offs or use standard pin sizes, reducing costs further?
2- Can we reduce wall thickness? Previously we looked at uniform wall, now can we reduce the average wall thickness or use methods to reduce wall thickness sections. The results are now two fold, less material within our part and cycle time reduction to produce our part, both saving monies in the manufacture of the part.

****Ideally the above two points should be concurrent of the part design, as this would alleviate the changes to other fits and function of parts but this than would also require folks to have been pre qualified to build the tool and or process the parts. This than means a partnership or relationship is established or being established, not a bad thing but not always thought of. This is the dilemma in where to involve others, an issue that has been fought over my entire career to be honest.

Further areas to consider within the tool build and part:

1- Gate location. If the part is cosmetic avoid having the gate in an area which could cause cosmetic issues. Also if the part is stressed in the application, gate location again has to be considered, as placing it at a stress point is not good. (mold flow, CAE)
2- Gas escape, venting within tool. This has to be looked at, too many times it is so easy to just burn the detail into the mold but than it is the last place to fill and this leads to a gas trap and burning of the plastic.
3- Cooling of the steel. How and where are we going to place cooling lines? Proper distribution of the coolant is critical to cycle times and warpage of our parts. Always place prior to step 4.
4- Ejection of the part after cooled. How and where can we place our ejector pins, sleeves, blades or other means to eject the part? Well the witness mark be okay on the part, well the pin be big enough so as to not slow down cycle time. What force well it take to get our part out the mold, understand that smaller the pin the higher a force it exerts.

Thanks for the time.

Steven L Silvey
Silveys Plastic Consulting
360-882-3183
silveysplastics@aol.com / silveysplastics@hotmail.com

SPE Members to be Inducted into The Plastics Hall of Fame

Congratulations are extended to SPE members Bob Barr (Extrusion Division), Paul Colby (Injection Molding Division), Ralph Noble (Past President of SPE), Bob Swain (Rotational Molding Division) and Don Witenhafer (Engineering Properties & Structure Division) on their election to The Plastics Hall of Fame.  They, and four other individuals (Trevor Evans, Paolo Galli, James Hendry and Georg Schwarz), will be inducted at The Plastics Hall of Fame Banquet at NPE on Monday, June 21, 2009, in Chicago, IL.

ANTEC Registration

All registration categories for ANTEC are open for members and nonmembers. ANTEC registration includes admittance to the NPE Exhibition and a copy of the Show Directory. Visit the SPE website to register.

ANTEC™ Technical Session Schedule Now Available

Approximately 130 sessions, comprised of podium and poster presentations, tutorials, and panel discussions, will be offered in 35+ technical areas at ANTEC™@NPE.  Specific session and presentation titles, dates, and times will be posted on the ANTEC™ website in the coming weeks.

Technical Seminars Offered at ANTEC@NPE2009

Make plans now to attend any of numerous educational courses pertaining to all aspects of the plastics industry. Choose among 30 seminars, including two offered in Spanish for the first time. Complete information detailing purpose, overview, content, the instructor’s expert background, and more can be found on the SPE website.

Honored Service Members and Fellows Elected

SPE is pleased to announce the election of 14 new Honored Service Members and nine new Fellows of the Society. They are listed below with their nominating groups.

Honored Service Members:

Robert Beard, Injection Molding Division; Mark Berard, Vinyl Plastics Division; Russell Broome, Piedmont Coastal Section; Dale Brosius, Thermoset Division; Frank Cangelosi, Polymer Modifiers & Additives Division; Jerry Fischer, Mold Making & Mold Design Division; Ken Kerouac, Mid-Michigan Section; Francis McAndrew, Palisades-New Jersey Section; Scott Peters, Mold Making & Mold Design Division; Monica Prokopyshen, Automotive Division; Vishu Shah, Southern California Section; Tim Simko, Composites Division; Clarence Smith, Southern California Section; and William Smith, Southern Section.

Fellow-of-the-Society Members Elected:

Jose Castro, Thermoset Division; Shia-Chung Chen, Injection Molding Division; George Epstein, Southern California Section; Douglas Hirt, Polymer Modifiers & Additives Division; Rajendra Krishnaswamy, Engineering Properties & Structure Division;  Patrick Mather, Polymer Analysis Division; Evan Mitsoulis, Extrusion Division; Bruce Muller, Rotational Molding Division; and Rajen Patel, Engineering Properties & Structure Division.
They will be formally recognized at the SPE Celebrates Luncheon on June 21, 2009, at the Palmer House Hilton in Chicago, IL.  Congratulations are extended to each one!

Respectively Submitted,
Brian Scappaticci
GGS Councilor
brian@sse-web.com

A Word from Our Education Chairman

Over the past month or so, our Chico State chapter has been developing tooling to create bottle openers and can openers. At our meetings we have been discussing design ideas and criteria, along with possible material selection, and potential processing parameters that might be used. Currently, we have made several revisions to current models and have created two rapid prototypes for the plausible parts.

By using rapid prototyped models, it enables a for constructive discussions. Group members are able to interact with tangible models and discuss mold considerations. At this point in our project, we have been discussing the plausibility of using multiple cavity molds with either one part or both. We determined that by using similar geometry and similar size parts, we have the potential to create both parts in each cycle.

We have decided that using a MUD die would be optimal for parts our parts. Discussions with faculty and members helped us realize that using the available resources we have would facilitate easier completion of our project. After Spring Break concludes, we will be holding a pizza meeting to finalize part design.

We plan on having a mold by the end of the year that can be used in our polymer classes as a learning tool and as inspiration for the club to create products that everyone can use!

Sincerely,

Mike Rincone, SPE President
 

Sincerely,
Joe Greene, Professor
California State University, Chico
jpgreene@csuchico.edu

The rotational molding process is a high temperature, low pressure plastic forming process that uses heat and biaxial rotation (i.e. rotation on two axes) to produce hollow, one piece parts.

Critics of the process point to it's long cycle times- only one or two cycles an hour can typically occur, as opposed to other processes such as injection molding, where parts can be made in a few seconds. The process does have distinct advantages though. The manufacture of large, hollow parts such as oil tanks is much easier by rotational molding than any other method. Rotational molds are significantly cheaper than other types of mold too- in the order of hundreds of US Dollars, rather than thousands as for other polymer processing molds.

The rotational molding process consists of four distinct phases:

1- Loading a measured quantity of polymer (usually in powder form) into the mold.

'2- Heating the mold in an oven whilst it rotates, until all the polymer has melted and adhered to the mold wall. The length of time the mold spends in the oven is critical- too long, and the polymer will degrade, reducing impact strength. If the mold spends too little time in the oven, melting of the polymer may be incomplete. The polymer grains will not have time to fully melt and coalesce on the mold wall, resulting in large bubbles in the polymer. This has an adverse effect on the mechanical properties of the finished product.

3- Cooling of the mold, usually by fan. This stage of the cycle can be quite lengthy too- the polymer must be cooled to a temperature where it solidifies and can be handled safely by the operator. This typically takes tens of minutes. The part will shrink on cooling, coming away from the mold, and facilitating easy removal of the part. The cooling rate must be kept within a certain range- very rapid cooling (e.g., by water spray) would result in the part cooling and shrinking at an uncontrolled rate, producing a warped part.

4- Removal of the part.

Recent Improvements in Rotational Molding

Until recently the process was largely empirical, relying on both trial and error and the experience of the operator to judge when the part should be removed from the oven, and when it was cool enough to be removed from the mold. However technology has improved in recent years which allows the internal air temperature in the mold to be monitored, removing much of the guesswork from the process.

Much of the current research is looking into lowering the long cycle times as well as improving part quality. The most promising area is within mold pressurisation- it is well known that applying a small amount of pressure internally to the mold at the correct point in the heating phase of the cycle speeds up the coalescence of the polymer particles during the melting phase, producing a part with less bubbles in a shorter period of time than at atmospheric pressure. This pressure also delays the separation of the part from the mold wall due to shrinkage during the cooling phase, aiding removal of heat from the part and therefore speeding the cooling phase too. The main drawback to this is the danger of explosion of a pressurised part to the operator- something that has prevented mold pressurisation becoming adopted on a large scale by rotomolding manufacturers.

Are You Using the Most Current Membership Application?

The SPE Council, as part of the 2009 budget process, approved a dues increase. Effective April 1, 2009, new members pay $144.00, which includes a one-time $15.00 initiation fee. Student and Emeritus member dues are $31.00, and all other renewing members are $129. The cost for additional Divisions remains $10.00 each per year.

The SPE membership application has been updated to reflect the dues increase. Please discard any other applications you have and use the new one. Download the current Section application or Division application. These applications are also posted on the membership area of the leadership services webpage and the newsletter editor resource page.

Sheet extrusion is a technique for making flat plastic sheets from a variety of resins. The thinner gauges are thermoformed into packaging applications such as drink cups, deli containers, produce trays, baby wipe containers and margarine tubs. Another market segment uses thick sheet for industrial and recreational applications like truck bed liners, pallets, automotive dunnage, playground equipment and boats. The third primary use for extruded sheet is in geomembranes, where flat sheet is welded into large containment systems for mining applications and municipal waste disposal.

Thermoplastic sheet production is a significant sector of plastics processing. Thermoplastic sheets are flat, plastic materials with a gauge of at least 250 microns and which include both flexible and rigid materials, as well as solid, foamed, and hollow materials.

Solid sheet extrusion units consist of at least one extruder and one sheet extrusion die. They are followed by the polishing stack, in general comprising 3 calenders, calibrating and cooling the sheet with their surfaces or calender nips. Behind this the roller conveyor and the draw-off rolls for air cooling are located. The sheet is finally cut and stored. Sheet extrusion characteristics:

width in excess of 2 m
thicknesses ranging from approx. 0.5 to 15 mm
no limitations as to length
setup as multilayer sheets with functional surfaces (colour, haptics, UV-protection ...)
grain/structured surfaces
easier forming possible (corrugated panels, folding, thermoforming ...)

SPE and ANTEC Groups Continue To Grow on LinkedIn® and Facebook®

If you're a member of LinkedIn or Facebook, join the Society of Plastics Engineers and ANTEC™ Groups and display their logos in your profile.

acelliboro Rubber is an elastic hydrocarbon polymer which occurs as a milky emulsion (known as latex) in the sap of a number of plants but can also be produced synthetically.

Synthetic rubber comprises the polymerisation of a variety of monomers to produce polymers. These form part of a broad study covered by Polymer science and Rubber technology.

The major commercial source of natural latex used to create rubber is the Para rubber tree, Hevea brasiliensis (Euphorbiaceae). This is largely because it responds to wounding by producing more latex. Henry Wickham gathered thousands of seeds from Brazil in 1876 and they were germinated in Kew Gardens, England. The seedlings were sent to Colombo, Indonesia and Singapore.

Other plants containing latex include figs, (Ficus elastica), euphorbias, and the common dandelion. Although these have not been major sources of rubber, Germany attempted to use such sources during World War II when it was cut off from rubber supplies. These attempts were later supplanted by the development of synthetic rubber. Its density is 920 kg/m3.

In places like Kerala, where coconuts are in abundance, the shell of half a coconut is used as the collection container for the latex. The shells are attached to the tree via a short sharp stick and the latex drips down into it overnight. This usually produces latex up to a level of half to three quarters of the shell. The latex from multiple trees is then poured into flat pans, and this is mixed with formic acid, which serves as a coagulant. After a few hours, the very wet sheets of rubber are wrung out by putting them through a press before they are sent onto factories where vulcanization and further processing is done.

Aside from a few natural product impurities, natural rubber is essentially a polymer of isoprene units, a hydrocarbon diene monomer. Synthetic rubber can be made as a polymer of isoprene or various other monomers. Rubber is believed to have been named by Joseph Priestley, who discovered in 1770 that dried latex rubbed out pencil marks. The material properties of rubber make it an elastomer and a thermoset.

Polymethyl methacrylate (PMMA) or poly(methyl 2-methylpropenoate) is the synthetic polymer of methyl methacrylate. This thermoplastic and transparent plastic is sold by the tradenames Plexiglas, Perspex, Plazcryl,Acrylite, Acrylplast, Altuglas, and Lucite and is commonly called acrylic glass or simply acrylic. The material was developed in 1928 in various laboratories and was brought to market in 1933 by the German Company Rohm and Haas (GmbH & Co. KG).

The material is often used as an alternative to glass. Differences in the properties of the two materials include:

PMMA is lighter: its density (1190 kg/m3) is about half that of glass.
PMMA does not shatter
PMMA is softer and more easily scratched than glass. This can be overcome with scratch-resistant coatings.
PMMA can be easily formed, by heating it to 100 degrees Celsius.
PMMA transmits more light (92% of visible light) than glass.
Unlike glass, PMMA does not filter UV (ultraviolet) light. PMMA transmits UV light, at best intensity, down to 300 nm. Some manufacturers coat their PMMA with UV films to add this property. On the other hand, PMMA molecules have great UV stability compared to polycarbonate.
PMMA allows infrared light of up to 2800 nm wavelength to pass. IR of longer wavelengths, up to 25,000 nm, are essentially blocked. Special formulations of colored PMMA exist to allow specific IR wavelengths to pass while blocking visible light (for remote control or heat sensor applications, for example).
PMMA can be joined using cyanoacrylate cement (so-called "Superglue"), or by using liquid di- or trichloromethane to dissolve the plastic at the joint which then fuses and sets, forming an almost invisible weld. PMMA can also be easily polished to restore cut edges to full transparency.

To produce 1 kg of PMMA, about 2 kg of petroleum is needed. In the presence of air, PMMA ignites at 460° C and burns completely to form only carbon dioxide and water.

If hydrogen atoms are substituted for the methyl groups (CH3) attached to the C atoms, poly(methyl acrylate) is produced. This soft white rubbery material is softer than PMMA because its long polymer chains are thinner and smoother and can more easily slide past each other.

Increase your knowledge of the plastics industry and improve your job performance, all from the convenience of your home or office. Internet access/phone line required. The following WEBINARS are scheduled in May 2009:

Engineering Design With Polymers
May 6, 2009
11:00am - 12:00pm

Polymer Film Testing: Techniques and Analysis
May 7, 2009
11:00am - 12:00pm

Strategies for Replacing Lead- and Chrome-Based Pigments in Synthetic Turf
May 13, 2009
11:00am - 12:20pm

Fuel Cells: Engineering Challenges & Opportunities
May 14, 2009
11:00am - 12:00pm
 
Troubleshooting for Plastics & Polymers
May 20, 2009
11:00am - 12:00pm
 
Understanding Bioplastics and Property Modification With Additives
May 21, 2009
11:00am - 12:00pm  

For more information and to register, please CLICK HERE

SPE is pleased to announce a new subscription plan for the e-Learning Center that will make it even more affordable for you to learn and stay competitive in your field! This plan will offer unlimited, affordable access to live technical presentations over the Web!  The subscription program will grant you VIP access to as many e-Live® Webinars as you like during a 3-month period. For more information, please contact Elizabeth Reagan (+1 203-253-1368).

Five legendary faculty of the UMass Lowell Plastics Engineering Department will be honored at a reception during the week of the co-located National Plastics Exposition (NPE) June 22-26, 2009 and the Society of Plastics Engineers Annual Technical Conference (ANTEC) June 22-24, 2009 in Chicago.

Profs. Rudy Deanin, Aldo Crugnola, Stephen Orroth, Stephen Driscoll, and Nick Schott have more than 200 years of combined educational service at LTI, ULowell and UMass Lowell. It was Russ Ehlers who founded the Plastics Department, but these “second-generation” of plastics educators at the University, have passed on their vast knowledge and dedication to those they’ve mentored and worked alongside for so many years. Some of the many alumni they taught and influenced will be on hand to wish them well.

For more information, contact Gail_Sheehy@uml.edu in the Plastics Engineering Department or call 978-934-3420.

For a view of the event in a PDF format, go to: http://www.4spe.org/sites/default/files/UMLevent.pdf

More than 750 presentations in 128 sessions are scheduled for ANTEC 2009, including 64 papers in the Commercial category. The number and quality of the papers are truly outstanding this year. For example, the Injection Molding Division is moderating 14 sessions with a total of 103 presentations on a variety of topics, including multi-component and co-injection processing, process control and automation, computer simulations, in-mold decorating, and injection screw designs.

Three New Technology Forums and a Fundamentals Forum will be presented. On Monday, a series of presentations on bio-sustainable materials is scheduled, followed by a panel discussion. Tuesday afternoon’s forum will feature Plastic Microfluidics — A Transformative Technology for Tomorrow. On Wednesday, a forum on Funding New Technologies: Insights from Venture Capitalists, Institutional Investors, and Investment Funds will examine trends in the plastics industry through a panel presentation and discussion. The Fundamentals Forum on Monday afternoon will cover innovations and inventions in polymer processing.

Also on Monday afternoon, an open panel discussion session on fatigue analysis and prevention will be moderated by Dr. Paul Gramann. Dr. Gramann encourages attendees to bring failed parts to be evaluated. Four experts in materials, design, testing, and processing will be on the panel.

A special session on the complex regulations and global impact of REACH (Registration, Evaluation, Authorization, and Restriction of Chemicals) is scheduled for Wednesday morning. REACH is a new initiative from the European Chemicals Agency for assessing and managing the hazards to health and the environment posed by chemicals.

For authors, a guide to presenting your ANTEC paper is available at the link below. This guide is in presentation form, provides many suggestions on formatting, and can be used as a template for ANTEC talks.

http://www.4spe.org/conferences/antec-2009

Mark A. Spalding
2009 ANTEC Technical Program Chairman
The Dow Chemical Company

MAY 2009

May 12 -15, Irvine
TA Instruments Theory and Applications Training Courses
Topics cover DSC, Modulated DSC, TGA, and Rheology
http://www.regonline.com/CalendarNET/EventCalendar.aspx?EventID=113925&view=Month
http://www.tainstruments.com/main.aspx?id=126&n=3&siteid=11

May 17-21, Portland
International Symposium on Capillary Chromatography and Electrophoresis
http://www.casss.org/displayconvention.cfm?conventionnbr=6042

May 27, San Jose
"Photovoltaics Technology and Manufacturing"
http://www.semitracks.com/courses/photovoltaics_technology.htm

Polysulfone, or PSU, is a polymer thermoplastic material. It is tough, rigid, high-strength, and transparent, retaining its properties between -100 °C and +150 °C. It has very high dimensional stability; the size change when exposed to boiling water or +150 °C air or steam generally falls below 0.1%. Its glass transition temperature is 185 °C.

Chemically, polysulfone consists of repeating units of C27H22O4S. It is produced by step polymerization of Bisphenol-A and bis(4-chlorophenyl)sulfone, forming a polyether by elimination of hydrogen chloride.

Polysulfone is highly resistant to mineral acids, alkali, and electrolytes, in pH ranging from 2 to 13. It is resistant to oxidizing agents, therefore it can be cleaned by bleaches. It is also resistant to surfactants and hydrocarbon oils. It is not resistant to low-polar organic solvents (eg. ketones and chlorinated hydrocarbons), and aromatic hydrocarbons.

Due to its excellent electrical properties, polysulfone is used as a dielectric in capacitors.

Mechanically, polysulfone has fairly high compaction resistance, allowing its use under high pressures.

Polysulfone allows easy manufacturing of membranes, with reproducible properties and controllable size of pores. Such membranes can be used in applications like hemodialysis, waste water recovery, food and beverage processing, and gas separation.

Polysulfone can be reinforced with glass fibers. The resulting composite material has twice the tensile strength and three time increase of its modulus.

Polysulfone can be used in FDA-recognized devices. It is used in medical devices, food processing, feeding systems, and automotive and electronic industry.

Polysulfone has the highest service temperature of all melt-processable thermoplastics. Its resistance to high temperatures gives it a role of a flame retardant, without compromising its strength that usually results from addition of flame retardants. Its high hydrolysis stability allows its use in medical applications requiring autoclave and steam sterilization. However, it has low resistance to some solvents and undergoes weathering; however the weathering instability can be offset by adding other materials into the polymer.

Polysulfone was introduced in 1965 by Union Carbide. It is a specialty material with very small share of the total plastics market. It is very expensive both as raw material and to process, therefore it is generally not used in applications that do not call for its special properties. In such applications, it is often a superior replacement for polycarbonates.

2011 - Boston, MA
2010 - Orlando, FL
2009 - San Antonio, TX

Conventionally, plastics are made of fossil fuel. These conventional types of plastics are heavily used worldwide – mainly in packaging and household applications. The benefits of low production costs, light weight, strength, relative imperviousness to gas and water, clarity, and printability are highly regarded, but the final disposal of used flexible plastics causes problems. The ever increasing use of plastics, particularly in packaging, has become a significant source of environmental pollution (litter) and created problems in waste management. If disposed of by landfill, the plastics worsen the shortage of landfill sites. If the plastics are incinerated, they can emit poisonous gases such as dioxins. These problems motivate the public to take more care of the environment. Making plastic bags biodegradable is one way to try to ease the task of waste reduction.

There are two main options for making normal polythene into a biodegradable film:

(1) Starch based or Biobased (Hydrodegradable)
It is made from corn (maize), potatoes, wheat. This form of biodegradable films meets the ASTM standard (American Standard for Testing Materials) and European norm EN13432 for compostability as it degrades at least 60% within 180 days or less.

Examples of polymers with which starch is commonly used:
Polycaprolactone (PCL)
Polyvinyl alcohol (PVA)
Polylactic acid (PLA)
These materials predominantly require a controlled microbial environment such as an industrial compost facility before they will degrade. The heat, moisture and aeration one gets in a compost pile are vital to this type of biodegradable film working well.

Pros & Cons of Starch based to Additive based film/bag
Pros:
Degradable & Compostable
No fossil fuel or very little fossil fuel (if % mixed with traditional polymer)
Faster degradation
Cons:
Poorer mechanical strength than additive based example – filling a starch bag with wet leaves and placing curbside can result in the bottom falling out when a hauler picks it up.
Limited Shelf life
Can only be composted in a special composting facility.

Typical Application area
Industrial Compostable Facility, Please visit your local city government's website to see if you have an industrial composting facility that accepts residential compost.

(2a)Additive based (Oxodegradable/Photodegradable)
These films are made by blending an additive to provide a UV / oxidative and/or biological mechanism to degrade them. This typically takes 6 months to 2 years in a landfill site and/or standard composting system. In these films, biodegradation is a two stage process; first the plastic is converted by reaction with oxygen (light, heat and/or stress) to molecular fragments that water can wet, and then these smaller oxidized molecules are biodegraded, i.e. converted into carbon dioxide, water and biomass by microorganisms.

Pros & Cons of Additive based to Starch based film/bag
Pros:
Cheaper & Proven
Controlled degradation
These films look, act and perform just like their non-degradable counterparts, except they break down after being discarded.
Cons:
Made using fossil fuel
Degradation depends on conditions of heat, light, stress, air etc

Typical Applications
Trash Bags, Garbage Bags, Compost Bags, Carrier bag, Agricultural Film, Mulch Film

(2b) Additive Based (Biodegradable)
Films made by blending an additive to provide a mechanism to attract microbes to biodegrade them. This typically takes in 1 year to 5 years in a landfill site and/or standard composting system.

Pros & Cons of Additive based to Starch based film/bag
Pros:
Cheaper & Proven
Useful shelf life until discarded in a landfill or microbial environment
These films look, act and perform just like their non-degradable counterparts, except they break down after being discarded.
Is not affected by light, heat, mechanical stress, or moisture.
Cons:
uses fossil fuel

The on-line version of the SPE GGS Spearhead is published 10 times a year. All rights are reserved. Errors and omissions are regrettable and will be corrected if possible. We reserve the right to edit any submissions. No form of this newsletter may be copied or reproduced without the written consent of the SPE GGS. To submit articles, information, corrections, or additions to the on-line Spearhead, contact spearhead@spe-ggs.org.