Today's KNOWLEDGE Share : CIRCULAR RECYCLING

-

Today's KNOWLEDGE Share

I recently attended a presentation where many "passes" of processing of a PP were examined to understand the issues related to "circular recycling" where the same polymer would go around the circle of manufacturing, shredding and reprocessing possibly...forever.


There was no mention however of a very important and critical factor : additives consumption.


With almost no exceptions (PVDF might be one), all plastics are compounded into pellets with various additives, particularly to protect the polymer from oxidation and other degradation paths during processing (high T, high shear stresses, long residence times,...).


The bulk of these additives are actually "consumed" during processing (for instance to capture free radicals and terminate reactions).

As a result, sending the material into an endless loop without replenishing the compound with fresh amounts of additives will always lead to quick degradation and loss of properties.


Differential Scanning Calorimetry can be used to perform a standard test (Oxidation Induction Times Test, in short :OIT) on PP to assess the loss of additives and help define a reformulation strategy.


So in conclusion, NO, you cannot just reprocess a polymer many times without reformulating appropriately.


Any studies on recycling that do not account for this are basically useless and not representative of the future needs of our industry where regulations are moving fast towards mandatory increasing recycling fractions to be used in production, particularly in Automotive with recent Eu rules.


source: Vito leo

Comments

Post a Comment

Popular posts from this blog

SABIC OPENS MULTI- MILLION-DOLLAR ULTEM™ RESIN MANUFACTURING FACILITY IN SINGAPORE

-
Image
SABIC, a global diversified chemicals company, today announced the official launch of its new US$170 (S$220) million ULTEM™ resin manufacturing facility in Singapore, marking the company’s first advanced specialty chemical manufacturing facility in the region producing the high-performance thermoplastic, ULTEM™ resin. The new facility is a strategic move to support SABIC’s goal of increasing global ULTEM™ specialty resin production by more than 50%, responding to the growing demand from high-tech and manufacturing industries in the Asia-Pacific region, including Japan and China. The facility opening was officiated by Ms. Low Yen Ling, Senior Minister of State for the Ministry of Trade and Industry (MTI) and Ministry of Culture, Community and Youth (MCCY), Eng. Khalid H. Al-Dabbagh, Chairman of the Board of Directors of SABIC, Eng. Abdulrahman Al-Fageeh, SABIC Chief Executive Officer, and Mr. Omar Al-Harthi, Deputy Head of Mission, Embassy of the Kingdom of Saudi Arabia in Singapore...
Read more

Today's KNOWLEDGE Share : Researchers Create Deployable Silk Fibers for Adhering and Lifting Objects

-
Image
Today's KNOWLEDGE Share The stream of liquid silk quickly turns to a strong fiber that sticks to and lifts objects These sticky fibers, created at the Tufts University Silklab, come from silk moth cocoons, which are boiled in solution and broken down into their building block proteins called fibroin.The silk fibroin solution can be extruded through narrow bore needles to form a stream that, with the right additives, solidifies into a fiber when exposed to air.  Nature is the original inspiration for deploying fibers of silk into tethers, webs, and cocoons. Spiders, ants, wasps, bees, butterflies, moths, beetles, and even flies can produce silk at some point in their lifecycle.Nature also inspired the Silklab to pioneer the use of silk fibroin to make powerful glues that can work underwater, printable sensors that can be applied to virtually any surface, edible coatings that can extend the shelf life of produce,a light collecting material...
Read more

Today's KNOWLEDGE Share : biobased content of polycarbonate diols

-
Image
Today's KNOWLEDGE Share MCG increases biomass content of polycarbonate diols Mitsubishi Chemical Group (MCG) has introduced grades of its Benebiol biomass-based polycarbonate diols that have a higher biomass content. The product is primarily used in the manufacture of polyurethane resins for coatings in sectors such as automotive, furniture and outdoor products. It is also used in the production of artificial leather. Existing Benebiol grades had a bio-based content of 20-50%, but the new HSS and NLDS grades have a biomass content in excess of 80%. Some of its previous petroleum-derived grades have also been converted to biomass, as the NLS grades. This, the company said, allows it to offer bio-based grades of all its Benebiol products. The shift to biomass-based raw materials while maintaining high-quality functions will contribute to our customers’ efforts to achieve sustainable manufacturing. source:MCG/www.utech-polyurethane.com
Read more