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An Overview of Poly(lactic acid) (PLA) in the Consumer Product

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Presentation on theme: "An Overview of Poly(lactic acid) (PLA) in the Consumer Product"— Presentation transcript:

1 An Overview of Poly(lactic acid) (PLA) in the Consumer Product
遠東企業研究發展中心 張莉苓 博士

2 Traditional raw material source
Why use PLA?  Environmental Protection: biodegradable reduce greehouse gas emission by 80-90% to the atmosphere compared to traditional plastics  Energy:  raw material is from renewable sustainable resource and not from fossil fuel  consume 62-68% less fossil fuel resources than traditional plastic Traditional raw material source NatureWorks’ current raw material source for fibers

3 Degradation

4 聚乳酸玉米纖維 遠東新世紀以其一貫的環境承諾,持續地追求新產品的研究與開發,以回應客戶不斷增加對綠色設計、自然空間、以及友善環境等的強烈需求。 遠東紡織公司2003年獨家獲得美國NatureWorks公司授權,臺灣使用該公司以玉米澱粉為原料,經發酵技術合成生產IngeoTM聚乳酸纖維(PLA Fiber)。 聚乳酸玉米纖維是一種新開發、引人注目的環保型纖維。除具有熱可塑性、生物可降解、可堆肥外,聚乳酸纖維還具有與聚酯和尼龍纖維相匹配的力學性能。

5 Outline Chemistry & Thermal properties of PLA
Melt spinning of poly(lactic acid) fiber Application & Modification of PLA Environmental Sustainability

6 如何製造PLA? Polymer Corn Fermentation Lactic Acid

7 Polylactic Acid (PLA) PLA belongs to the family of aliphatic polyester, and it is considered biodegradable and compostable. (i.e. ability of degrading a material under the action of microorganism in a humid environment to produce biomass and carbon dioxide) PLA is a thermoplastic, high strength, high modulus polymer which can be made from annually renewable resources to yield articles for use in either the industrial packaging field or the biocompatible/bioabsorbable medical device market.

8 Production of lactic acid from renewable resources

9 Lactic Acid Structure (S)L(+)Lactic Acid (R)D(-)Lactic Acid
(Dextrorotatory) (R)D(-)Lactic Acid (Levorotatory)

10 Method to produce High-Mw (PLA):
Polycondensation route & ROP route: Direct condensation polymerization Chain coupling agents Low Mw Prepolymer Mw=1,000~5,000 L-lactic acid Azeotropic dehydration codensation Polymerization Through lactide formation High Mw Polymer Mw>100,000 D-lactic acid Ring Opening Polymerization Low Mw Prepolymer Mw=1,000~5,000 Lactide Ref. Macromol. Bioscience 2004, 4,

11 Ref. Macromol. Bioscience 2004, 4, 835-864
Current Production Process for PLA : Fermentation Distillation Lactic acid Prepolymer Unconverted Polymer Dextrose Polymerization Distillation Coordination/ Insertion Propagation PLA polymer Ref. Macromol. Bioscience 2004, 4,

12 Physical, Mechanical, and Barriers
Polymer Properties Physical, Mechanical, and Barriers

13 Physical Properties Properties PLA Molecular Weight (Daltons)
Glass Transition Temperature (oC) 55-70 Melting Temperature (oC) Crystallinity 10-40% Surface Energy (dynes) 38 Solubility Parameters (J0.5cm-1.5) Heat of melting (J g-1) Specific Gravity 1.25 Melt-Index range (g/10min) 2-20

14 Thermal properties of PLA with different optical purity of Lactate units
◆:Tm;●:Tg Amorphous [L]=90% [L]=12% Ref. Macromol Mater Eng 2001, 286, Macromol Mater Eng 2003, 288,

15 Mechanical Properties
L-PLA D,L-PLA Yield Strength (Mpa) 70 53 Tensile Strength (Mpa) 66 44 Elongation at Break (%) Flexural Strength (Mpa) 119 88 Notched Izod Impact (J m-1) 18 Vicat Penetration (oC) 165 52

16 Comparison Properties PLA PS PVC PP Yield Strength, MPa 49 35
Elongation, % 2.5 3.0 10 Tensile Modulus, GPa 3.2 3.4 3.6 1.4 Flexural Strength, MPa 70 80 90

17 Barrier Properties Permeability PLA
Oxygen, cc-mil/m2*day*atm (ASTM D1434) 550 Carbon Dioxide, cc-mil/m2*day*atm (ASTM D1434) 3,000 Water, g-mil/m2*day*atm (ASTM E96) 325

18 Degradation

19 Principle of microbial polyester degradation

20 Degradation

21 Ref. Polymer Degradation Stability 1998, 59, 145-152
Hydrolysis of PLA: Ref. Polymer Degradation Stability 1998, 59,

22 Biodegradation of PLA in 60℃ Compost

23 Copolymer of (L-Lactide) and (D,L-Lactide)
Degradation Polymer Degradation Time Poly(L-Lactide) Months-years Poly(D,L-Lactide) Weeks-months Copolymer of (L-Lactide) and (D,L-Lactide) Poly(meso-Lactide) Weeks Poly(L-Lactic Acid)

24 Stereocomplexed PLA ScPLA

25 Synthesis of Stereocomplexed PLA
PLLA L-Lactic acid 1) Oligomerization 2) Melt Polycondensation 3) Melt or solvent Blending PDLA D-Lactic acid Sc-PLA Tm:220~230℃ Ref. Macromol. Bioscience 2005, 5, 21-29

26 Stereocomplexed PLA XD= 0.2 0.4 0.5 0.6 0.8 1  DSC thermograms of PLLA/PDLA blends with different XD values. Physical properties Sc-PLA PLLA PDLLA Tm (℃) --- Tom (℃) 279 Tg (℃) 65-72 50-65 50-60 Hm (100%) (J/g) 146 93-135 Tensile strength (GPa) 0.88 0.05 Young’s Modulus (GPa) 8.6 7-10 Elongation at break (%) 30 12-26 5-10 Ref. Macromol. Bioscience 2005, 5,

27 Stereocomplexed PLA Unit cell parameters for PLLA and Sc-PLA.
Space Group Chain orientation No of helices/unit cell Helical conformation PLLA α- form Pseudo-orthorhombic -- 2 103 Sc-PLA Triclinic Parallel 31 Crystal Structure of PLA stereocomplex Ref. Polym Int 2006, 55, Macromol Biosci 2005, 5,

28 Synthesis of Stereo-block PLA
L-Lactic acid D-Lactic acid 1) Oligomerization 2) Melt Polycondensation 3) Melt or solvent Blending PLLA PDLA Sc-PLA Tm:220~230℃ 3) Annealing 4) Melt solid-state Polycondensation Sb-PLA Ref. Macromol Biosci 2005, 5, 21-29

29 Stereo-block PLA  Comparison of DSC curves of PLLA, PLLA/PDLA
and sb-PLA Ref. Macromol. Symp , 224,

30 Stereo-block PLA Sc-PLA Schematic duagram for the solid-state structure of the solid-polycondensates. crystalline Monomer Stereo-block PLA Solid Polycondensation Ref. Macromol. Symp , 224,

31 scPLA Fiber Processing
Increased extrudsion temp. profile needed -SC~ ℃ vs. 6201D~ ℃ Better spinning performance/success…. -Higher TUS (e.g.-POY speeds vs. staple speeds -Lower stretch ratio (higher jet velocity) SC spinning window more like conventional melt spun polymers


33 Outline Chemistry & Thermal properties of PLA
Melt spinning of poly(lactic acid) fiber Application & Modification of PLA Environmental Sustainability

34 Comprehensive data on PLA fiber melt-spinning
Year Workers Process highlight 1972 Schneider Fiber with 0.69GPa tensile strength reported 1982 Eling Dry spun fibers show better properties compare to melt spinning 1984 Hyon et al. Tensile strength up to 0.7GPa 1992 Dauner et al. Tensile strength up to 0.4 GPa 1993 Penning et al. Absorbable fibers developed from L-lactide copolymers 1997 Fambri et al. Two stage process i.e. spinning and hot drawing 1998 Mezghani et al. Maximum take up speed achieved-5000 m/min 1999 Schmack et al. High speed spinning and spin drawing 2001 Cicero Continuous two-step melt spinning process Yuan et al. Two-step process (melt extrusion and hot draw) 2002 Two-step melt spinning process 2004 High speed melt spinning of various grades of PLA Ref. Prog. Polym. Sci. 32 (2007)

35 PLA fiber properties Appearance: Fibers are generally circular in cross-section and have a smooth surface. Density: The specific gravity is 1.25 g cm-3, lower than natural fibers and PET Refractive index: The refractive index of is lower than PET (1.54). Trilobal and other shapes can be made, and give improved antisoiling characteristics. Thermal properties: PLA is a stiff polymer at room temperature.

36 DSC scans of PET and PLA

37 PLA fiber melt temp. as a function of % D-isomer

38 PLA fiber properties Crimp: PLA can achieve good degree of crimp and good retention level through processing. Fiber types: Both filament yarns and spun yards can be made, as with PET. Tenacity: The tenacity at break (32-36 cN tex-1) is higher than for natural fibers although, of course, it can be varied according to the degree of drawing that is applied to the undrawn yarn. Tensile properties: The tensile properties of PLA fiber as used in staple from for textile processing.

39 Tensile Properties:

40 PLA fiber properties Moisture regain: At %, PLA has extremely low moisture regain, much lower than natural fibers and slightly higher than polyester. Flammability: Although PLA is not a non-flammable polymer, the fiber has good self-extinguishing characteristics; it burns for 2 min after a flame is removed, and burns with a white and a low smoke generation. PLA also has a higher LOI (limiting oxygen index) compared to most other fibers, meaning that it is more difficult to ignite as it requires a greater oxygen level. UV resistance: Unlike other synthetic fibers, PLA does not absorb light in the visible region of the spectrum; this leads to very low strength loss compared to petroleum-based fibers when exposed to UV.

41 Comparison of PLA and PET flammability properties:

42 PLA fiber properties Moisture transport: PLA shows excellent wicking ability. This property and the additional properties of fast water spreading and rapid drying capability give the fiber a very positive inherent moisture management characteristic. Biological resistance: Although PLA fibers are not inherently “antimicrobial” without suitable after-finish treatment, they do not provide a microbial food source. In addition, testing by Odor Science and Engineering showed that PLA fiber-based farics outperformed PET-based fabrics for low odor retention. Chemical resistance: AS PLA is a linear aliphatic fiber, its resistance to hydrolysis is therefore relatively poor. This feature means that care must be taken in dyeing and finishing of the fiber. Solubility: With regard to other chemicals PLA has limited solubility and is unaffected by dry-cleaning solvents for example.

43 Outline Chemistry & Thermal properties of PLA
Melt spinning of poly(lactic acid) fiber Application & Modification of PLA Environmental Sustainability

44 Application

45 Applications: Medical: →Suture →Prosthesis →Controlled Release
Packaging: →Retail bags →Disposables Caps →Containers →(Agrucultural mulch films) Textiles: →Shirt →Tags

46 Apparel (1) It is one of the features of PLA that it can be produced as both filament and spun yarns. Fabrics produced from spun yarn have a ‘natural’ hand and are considered to feel similar to cotton in this respect. (2) Fabrics from filament yarns have a cool and soft hand and exhibit a high fluidity or drape with a degree of elasticity. NatureWorks LLC product development suggests, for example, that a 1.2 dpf PLA achieves the softness of a microdenier PET (e.g. 0.7 dpf).

47 AATCC Test Method 61-1994 (35%PLA/65% cotton blend knitted shirt, simulates five washings):

48 Dyeing and Finishing (1) Similar to PET, PLA is dyed with disperse dyes. However, dye selection is most important, as the individual dye behavior is quite different from dyeing on PET. In general terms, dyes show their maximum absorption at a shorter wavelength than on PET and tend to look brighter. Dyes also show a much greater variation in exhaustion levels. The exhaustion of ten disperse dyes on PLA and PET fabrics and found that the percentage dye exhaustion of all the dyes was lower on PLA than on PET.

49 Dyeing and Finishing

50 Dyeing and Finishing (2) One of the observations in the dyeing of PLA is that obtaining dark shades is more problematic, compared to PET. A reason for this is attributable to the lower exhaustion levels, although, of course, dye selection has to balance many other factors including fastness requirements, reproducibility, and levelness. Deep dyed PLA

51 Outline Chemistry & Thermal properties of PLA
Melt spinning of poly(lactic acid) fiber Application & Modification of PLA Environmental Sustainability

52 Fossil energy requirement for some petroleum-based polymers and PLA

53 Global Climate Change

54 Water use

55 Conclusion PLA has a largest potential market because is a compostable and biodegradable thermoplastic. Study on PLA’s properties are necessary to be fully adapted in packaging applications.


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