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.

56. THANK YOU