Summary
SCRI Materials Working Group (MWG)
7/19/12
Prepared and Submitted by Doug Hayes, UTK, (with the assistance of …)
Attendees:
Jeremy Cowan
Doug Hayes
Karen Leonas
Larry Wadsworth
Feedstocks for PLA Biodegradable Mulches (BDMs)
a. 100% PLA Grade 6202D (donated to us), a conventional textile fiber spinning
grade with a melt index (MI) of 15-30 g/10 min, donated by NatureWorks and sent to
Saxon Textile Research Institute (STFI) in Germany to produce spunbond (SB) PLA
made in October 2009 for SCRI field and greenhouse studies in 2010.
b. 100% PLA Grade 6252D (MI of 70-85 g/10 min) purchased from NatureWorks at
a discount of $3.41/kg for samples to the commercial bulk price of $2.10/kg
(NatureWorks has a policy of charging $5.51/kg for PLA polymer samples), with a lower
MW than 6202D grade, leading to a smaller fiber size, hence enhanced degradation
relative to SB-PLA, due to the more assessable smaller fibers and the lower MW, and
will be easier to work with (than the previously used PLA feedstock) for manufacturing
due to its lower viscosity. Weight-average MW of 100,000 and MI of 70-85. (6251D is
the same as 6252D, except 6252D has a biodegradable pellet lubricant for easier
extrusion.)
c. 100% PLA used for Meltblown (MB) BDMs in 2009 and 2010: a blend of 80%
6201D / 20% 3251D from NatureWorks (6201D has a MI of 15-30; 3251D has a MI of
70-85),
d. PHA feedstock: GreenBio, Tianjin, China, co-polymer of 3-hydroxy butyrate and
4-hydroxy butyrate; the latter monomeric unit being present at < 30%. Weight-average
MW of feedstock is 600,000; however, the MW of the copolymer in the mulch material is
~300,000, due to degradation that occurs quickly during melt extrusion.
e. Carbon Black (STFI’s masterbatch concentrate mixed with 6252D produced at a
concentration of ~1-2 %%).
Mulch Materials for Upcoming Work.
a. Mulch Materials Listed in SCRI Proposal, for use by Growers in High Tunnel /
Field Studies
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BioBag Ag-Film, listed as “Treatment 1” in the SCRI Proposal (Palm Harbor,
FL; as per p. 11 of SREP proposal; commercially available BDM). Proper trade
name of biodegradable mulch film is BioAgri. Made from starch based resins
(e.g., corn, potato, wheat starches). Contains PBAT, poly(butylene
adipate-co-terephthalate), a petroleum-based, but compostable, polymer.
Thickness of 15 microns. Not OMRI certified for use in organic agriculture.
Certified for organic production in Europe and also certified to be fully
compostable by U.S. and European standards.
http://www.biobagusa.com/compostable-film.html
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BioTelo Agri, “Treatment 2” (Dubois Agrinovation, Waterford, Ontario, CAN,
commercially available BDM). Certified as “biodegradable” (“EcoCert”) and
“compostable”. Made from starch based resins (e.g., corn, potato, wheat
starches). Thickness of 15 microns. Annette has procured it.
http://www.duboisag.com/catalog/php?product_id=9
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Spunbond (“SB”) PLA, “Treatment 3”
o Product 1, SB-PLA-2010: 100% PLA Grade 6202D, 90 g/m2 thick white
colored; 5 rolls of 250 m x 40-45 inches. Prepared at STFI (Saxony
Textiles, Germany) in November of 2009.
o Product 2a, SB-PLA-2011: 100% PLA using 100% PLA = 6252D;
formulated with ~ 1-2% Carbon Black, 80 g/m2. Produced at STFI in early
Nov -10. 3 rolls shipped to Wszelaki, Miles/Leonas, and Wallace.
o Product 2b, SB-PLA-2011-white: = Product 2a, except it does not
contain Carbon Black .. manufactured at STFI in early Nov ’10. (1 x 250m
roll was made for physical test comparison to the black PLA SB and for
possible greenhouse studies)
o Product 3a, SB-PLA+PHA-2012: 80% PLA = 6251D + 20% PHA; PHA
prepared and extrusion compounded with 6251D PLA at Greenbio,
Tianjin, China and shipped to STFI. 1-2% carbon black was added during
extrusion at STFI and the fabric weight produced was 80 g m -2; 2 rolls of
250 m prepared at STFI in June, 2011, which was re-wound at STFI into 3
smaller rolls (150 m to Russ, 175 m to Annette (with 25 m going to Doug),
and 175 m to Carol (with 25 m going to Karen).
o Product 3b, SB_PLA + PHA-2012-white: 80% PLA = 6251D + 20%
PHA; 80 g m-2; 2 rolls of 250 m each prepared at STFI in June, 2011 (both
rolls shipped to Doug Hayes and 25m will be send to Karen Leonas and a
quantity to be requested by Carol Miles will be sent to her).
o
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Black Plastic Mulch, “Treatment 4”; Non-Biodegradable polyethylene, Pliant
Corp, Schaumburg, IL, 1.0 mil, serving as a control a now widely-used in
agriculture as a non-BDM control. http://www.pliantcorp.com/
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Note: “Treatment 5” = the absence of mulch (control for Growers and Soils
Working Groups).
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WeedGuardPlus, Cellulosic mulch (as a positive control; brown in color),
SunShine Paper Company, LLC, Denver, CO. 107 g/m2. Width of 46 in.
Reported to be “100% Biodegradable.” Contains heavy metals at ppm levels or
lower. Organic Materials Review Institute certified (“OMRI listed”) for certified
organic production. Rolls of 46 in x 1000 ft, 3, were sent to Annette (UTK), Russ
(Texas A&M/ Texas Tech), and Carol (WSU-Mt. Vernon). Mulch should be stored
so that it is not in contact with water; otherwise, no freezing or any other specific
requirements are needed. http://www.weedguardplus.com/
Carol obtained the idea of using a cellulose control through attending the
American Plasitculture Society Meeting, per suggestion of an Italian group
investigating Biobag and Biotelo. Ramani Narayan (Mich St. Univ; Advisory
Board member) was at the meeting and suggested the most important aspect of
a cellulose standard as a positive control is 100% biodegradability
a. Meltblown (“MB”) PLA-based mulches: used in Greenhouse studies at Univ.
Tennessee (Activity II-A)
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MB-PLA-2010. 75 g/m2, width = 12.5 inches. Manufactured by Biax-Fiberfilm,
Greenville, WI during using a blend of NatureWorks PLAs consisting of 80% PLA
6201D, and 20% PLA 3251D according to Larry’s instructions in November,
2009. (although not used in field and HT tests one roll was sent to Carol Miles,
Russ Wallace and Doug Hayes).
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MB-PLA-2011. As per Product 1, except for the use of a lower-MW PLA
feedstock (NatureWorks PLA 6252D), Prepared at Biax in November, 2010. 2
Rolls will be prepared, sent to Hayes, and kept at UTK.
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MB-PLA(85)+PHA(15)-2011. Meltblown PLA / PHA Blend 1, 85/15 w/w.
Extrusion compounded at Greenbio, Tianjin, China and processed into MB
nonwoven at Biax, Wisconsin, under the direction of Larry in November, 2010.
Using GreenBio PHA and PLA 6251D as feedstocks. 1 roll sent to Doug
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MB-PLA(75)+PHA(25)-2011. Meltblown PLA / PHA Blend 2, 75/25 w/w. As
described for Blend 1 (MB-PLA(85)+PHA(15)-2011), with the only difference
being the ratio of the 2 feedstocks. Prepared at Biax, Wisconsin, per Larry’s
instruction in November, 2010. 1 roll sent to doug
Old Business
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a. Publications by MWG members
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C. Miles, D. Miles, C., D. Hayes, J. Moore-Kucera, M. Brodhagen, T. Marsh, A.
Corbin, R. Wallace, A. Wszelaki, T. Walters, J. Lee, and D. Inglis. 2011.
Biodegradable alternatives to plastic mulch. In: Transforming Lives Transforming
Landscapes. The Business of Sustainable Water Buffer Management.
Steenbergen, F. van, A. Tuinhof and L. Knoop (Eds). Wageningen, The
Netherlands: 3R Water Secretariat, pp 84-89. isbn: 978-90-79658-00-8
Larry C. Wadsworth, Douglas G. Hayes, Annette L. Wszelaki, Tommy L.
Washington, Jeffery Martin, Jaehoon Lee, S. Dharmalingam, C. Tyler Pannell,
Carol Miles, and Debra Inglis, 2011, Evaluation of Biodegradable Spun-Melt
100% Polylactic Acid Nonwovens Mulch Materials in a Greenhouse Environment,
submitted to Journal of Engineered Fibers and Fabrics (based on UT
Greenhouse Study I, 2010; second revision of manuscript in preparation)
Douglas G. Hayes, Sathishkumar Dharmalingam, Larry C. Wadsworth, Karen K.
Leonas, Carol Miles, and Debra A. Inglis, 2012, Biodegradable Agricultural
Mulches Derived from Biopolymers, in Degradable Polymers and Materials,
Principles and Practice, 2nd Edition,\ (ACS Symposium Series, Volume
??),Kishan C. Khemani and Carmen Scholz, Eds., Washington, DC, American
Chemical Society, in press.
Hablote, Narayan, Dharmalingam, Hayes, Wadsworth, Miles, Inglis; Effect of
Weatherometry on Physico‐Chemical Properties and Inherent Biodegradation of
PLA/PHA Nonwoven‐Based Agricultural Mulches. To be submitted to Polymer
Degradation and Stability; to be written mainly by Hablote, then by Hayes.
Submission by mid‐Fall 12
Dharmalingam, Hayes (?), Wadsworth, Saxton, Wszelaki, Raley, Lee, Miles,
Inglis. On the Degradation of PLA/PHA‐based Nonwovens in Soil Burial Studies:
Effect of Soil Moisture, Enzymes, and Soil Temperature on Physico‐Chemical
Properties. To be submitted to same journal as above. To be written by
Wadsworth / Hayes. Based on current and ongoing Greenhouse Studies. This
may be broken into two manuscripts.
Same authors as above, On the Time Course of Degradation of PLA/PHA‐based
Nonwovens as Agricultural Studies in Soil Burial Studies, same journal (?), to be
written by Dharmalingam / Hayes during early Summer 13
Dharmalingam, PhD Dissertation, UT (late summer, 2013)
Leonas, Liu, Hayes, Wadsworth, Miles, Cowan, Wallace, Wszelaki, Inglis
Degradation of Agricultural Mulch: Comparison of Accelerated Laboratory
Weathering and Field Exposure, Journal of Environmental Polymer Degradation
Submission mid Fall 2012
Leonas, Liu, Hayes, Wadsworth, Accelerated Laboratory Weathering of
Agricultural Mulch Products, Journal of Polymer and the Environment – BETS –
Submission early Fall 2012
Leonas, Liu, Hayes, Wadsworth, Accelerated Laboratory Weathering of PLA
Nonwoven Fabrics, Textile Research Journal – Submission mid-Fall 2012
b. Other, joint WG manuscripts
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4.
Carol suggested preparing a manuscript in the future which would compare
measurements of physical deterioration [percent visual deterioration (PVD and
AUDPC) and counting the number of rips, tears and holes (TRH)] versus
mechanical strength testing. Jeremy’s work suggests that such a correlation
doesn’t exist. Jeremy and Carol are pursuing a paper for growers that relates the
absence of correlation. Jeremy sought our advice today.
Another paper suggested by Carol was a focus upon the correlation between
mulch physico-chemical data versus soil temperature/data
New Business
a. Karen / Hang (Washington St. – Pullman)
 All analyses from the 2010 and 2011 high tunnel / open field studies are
completed
 2012 HT and Open Field studies [tensile strength, elongation, and thickness
measured for all samples; weight (g/m2) for Time 0 and 1 only)]: Testing of all
Time 1 samples are complete; Time 2 samples are being tested (TX, TN samples
received).
 There has complete turnover of student workers in the lab and three new
students were hired this summer and have been trained. Two of the three are
graduate students in engineering. It was determined that with the quanitity of
work to be completed in a short deadline, these students have a shorter learning
curve and are better equipped to troubleshoot as issues arise.
 Weatherometery work is currently ongoing and will be completed by the end of
the week. Some malfunctions have delayed progress.
 Karen will aim to complete all work relating to this project by December 31,2012
b. Doug / Larry (Univ. Tennessee)
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Hayes and Wadsworth have requested a one-year no-cost extension with Debbie
Doug and Sathish submitted proposals to present (Doug= oral, Sathish = poster)
at the BioEnvironmental Polymer Society (BEPS)Meeting in September, 2012
(Denton, TX). Doug received a travel grant to attend this meeting through the UT
Institute of Agriculture.
Doug will be presenting at the ASHS symposium on mulches prepared by Carol:
31 Aug
Larry et al received the review of our revised manuscript to JEFF Journal and is
preparing the revisions.
Ms. Rachel Dunlap, an undergraduate research assistant, joined the team. She
completed the FTIR work, and some of the GPC analysis
Greenhouse Study 2b was recently finished. Experimental matrix consisted of 4
mulches (SB-PLA-2011, MB-PLA-2011, MB-PLA(85)+PHA15)-2011, and MBPLA(75)+PHA(25)-2011), 2 enzyme treatments (pineapple juice = bromelain, no
enzyme as control), 2 retrieval times (10 wk, 30 wk); 2 moisture level treatments;
2 replicates per experiment (4 x 2 x 2 x 2 x 2 = 64 samples). FTIR analysis
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completed. GPC analysis ongoing. Tensile strength testing is delayed due to
equipment problems at UT. SEM analysis (30 wk samples) is ongoing.
Greenhouse Study 3 will commenced in early January, 2012. Experimental
Design: 7 mulches (Biotelo, White Spunbond 2011, Black Spunbond 2011, PLA
Crowne film (Provided by Dick Mathis) ,100% PLA Meltblown (MB)-2011,75%
PLA MB,85% PLA MB-2011), 2 retrieval times (10 and 29 wk), 2 replicates; 7 x 2
x 2 = 28 samples. 10-week samples have been retrieved and are being
analyzed. Of note, the PLA film underwent extensive degradation.
Greenhouse Study 4 commenced in early July. Parameter Space:3 soil
temperatures (Greenhouse ambient; Greenhouse heated.. approx 15 F higher
than ambient via meating mats; Laboratory Ambient: approx 15 F cooler than
greenhouse ambient), 2 mulches (MB-2011 mulches: 75% and 100% PLA), 3
replicates (depending on anticipated precision of temperature control), 3 retrieval
times (54 trays)
Future Greenhouse Studies: head-to-head comparison of microbe-inactivated
soil vs control soil/compost; UV-treated mulches (led by Rob Raley for his PhD
dissertation); more expanded study of time / kinetics; study of PLA films vs
nonwovens
Collaborative work between Sathish, Doug, Larry, Ramani Narayan, and his
postdoc, Elodie Hablote: Doug and Sathish visited Narayan’s lab in July, with
Sathish staying there for 2 weeks. The experimental setup is as follows: The
treatment consists of 4 mulches: SB-PLA-11, SB-PLA-11-white, MB-PLA-11,
MB-PLA(75)+PHA(25)-11. Each of these mulches are currently being tested for
biodegradability via ASTM D5833 (ISO 14855-1) and treated via weatherometry
at MSU. (Experiments re-run due to equipment problems with D5833
equipment.) The weatherometry-treated mulches will then be subjected to
biodegradability testing. Suite of tests: FTIR, DSC, molecular wt (GPC), tensile
strength load and elongation. Sathish will go to MSU and help with the final
collection of data. Manuscript writing will begin early this fall.
GPC analysis of the 2010 and 2011 HT and Open Field samples (Biobag,
Biotelo, and SB-PLA-11 only): Completed; data and report on Intranet site. The
HT/OF samples from 2012 will be run in the fall.
We discovered that, due to the separation of GPC peaks for PLA and PHA, that
we can monitor the MW change of each biopolymer, and (through integration
plus use of a calibration), we can monitor the change in relative amounts of the
two biopolymers.
We have analyzed weatherometry-treated samples from Karen via GPC and
FTIR. After a final “quality control check” the data will be sent to Karen (soon).
Sathish is preparing a research proposal, as part of his qualifying exam for his
PhD degree. Exam will take place this fall.
Review of Proposal Deliverables for MWG
a. Activity I-A (Preparation and Distribution of SB nonwovens; Larry): Task has
been completed.
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b. Activity I-B (Physical / Mechanical Strength testing; Karen & Hang) Completed
c. Activity II-A (Greenhouse studies at UTK (Hayes, Wadsworth, and Wszelaki) A
first Greenhouse study has been completed, with a manuscript submitted. 2nd
4th greenhouse studies are ongoing. Other s planned.
d. Activity II-B (Weather resistance performance assessment of BDMs used in HT
/Open Field studies, Karen & Hang) In progress.
Activity II-C (ASTM Biodegradability testing of BDMs at Ramani’s lab at Mich
State and at UTK, Doug) Testing is ongoing.
e. Activity III-D (Physical/chemical analysis of BDMs in high tunnels / field studies)
All data for 2010 and 2011 are being collected. Karen and Hang are preparing a
manuscript.
f. Activity IV (Field Studies 2-4 Completed
6. The MWG may meet, perhaps virtually, in the latter part of the year for a final wrapup.
7. Miscellaneous / Announcements:
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Reminder: For public dissemination, cite
http://vegetables.wsu.edu/plasticulture.html as the website. For SCRI Team
Members, use: http://vegetables.wsu.edu/SCRI/team.html.
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