Presentation is loading. Please wait.

Presentation is loading. Please wait.

Synthesis of Polylactic acid

Similar presentations


Presentation on theme: "Synthesis of Polylactic acid"— Presentation transcript:

1 Synthesis of Polylactic acid

2 Production Direct condensation of lactic acid – single step
Ring opening polymerization- Multi step process

3 Feasible process for the commercial production of PLA
by Direct Condensation Equilibrium between free acid , Water, and polyesters Difficulty in removing the trace amount of water in the late stages of polymerization generally limit the ultimate molecular weight achievable by this approach To overcome the above Kinetic control over the reaction Efficient removal of Water : Reletively high temperatures Reduced pressure Entraining agent such as various solvents Suppresion of Depolymerization

4 Catalysts employed : Protonic acids Metals Metal Oxides Metal halides
Organic salts of metals

5 General properties of Polylactic acid O [CH-C-O]n CH3
Transperancy Glass Transition temperature C Melting Point C Crystallinity : % Tensile Strength : 4-6 Kg/mm2 Elongation : 3-4 %, brittle Flexural Strength : 9~11 Kg/mm2 Impact Strength :~50 Kg-cm/cm2

6 Bio-Polymer Production (Cargill-Dow, USA)
Production of Polylactic acid (PLA) polymer from corn sugar replaces petroleum feedstock. PLA can replace PET, polyesters and polystyrene. PLA is compostable. PLA is carbon neutral – CO2 is recycled. In the future, PLA will be made from ligno-cellulosic biomass.

7 Used for 30 years in medicine:
Background on P.L.A. Used for 30 years in medicine: Encapsulation of vaccines Carrier for slow release medication - treatment of prostate cancer and infertility

8 Polylactic Acid (PLA) A polymer made from cornstarch fermentation, declared a new generic fiber by the US FTC Competitive in price and performance with fossil fuel derived polymers: PE, PS, PP, polyester Can be engineered to be biodegradable Can be used in carpet tiles Cargill Dow's new facility in Blair, Nebraska, will use up to 40,000 bushels of corn each day and can produce more than 300 million pounds of PLA each year

9 Cargill-Dow LLC Plant. Blair, Nebraska. November, 2001. Completed
August, 2001 August, 2001 September, 2001 The School of Packaging Mechanical, Physical and Barrier Properties of Poly(Lactic Acid) RAA, © 2002

10 Main Producers Producer Cargill – Dow LLC 16 300 Mitsui Chemicals 1.3
2000 Million lb/yr* 2001 Million lb/yr ** 2002 Million lb/yr** Cargill – Dow LLC 16 300 Mitsui Chemicals 1.3 Cost U$S / lb 1.5/2.0 1.0 0.5 * Chemical Week V162, 2000 & Plastics Week, Jan17, 2000

11 Polylactic acid (PLA) for plastics production
Corn Starch Unrefined Dextrose Lactic Acid Fermentation Lactide Monomer Production Polymer Grades Fiber Film Thermoforming Bottle Woven Non-woven Etc. Polymer Modification Polymer Production PLA

12 Polymerization scheme of copolymers
from L-lactic acid and D-lactic acid

13 Recent development of biodegradable sutures

14 Non-Solvent Process to Prepare PLA
Fermentation By heating catalyst. Lactide Formation Lactic Acid Prepolymer Distillation Unconverted Polymer Meso Lactide Dextrose PLA Polymer Polymerization Distillation Coordination / Insertion Propagation Low D Lactide Corn Cargill Dow LLC Process. Gruber, et. al

15 Biodegradable polymers approved
for medical applications

16

17 PGA – Polyglycolic acid, PLA – Polylactic acid, PLGA – Copolymer of PLA & PGA

18 Initial cost of PLA was too high that has limited its
packaging applications to high value films, thermoformed containers, and coated papers . PLA has a largest potential market because it is a compostable and biodegradable thermoplastic. Derived from annually renewable agricultural resources . New technologies for mass production of PLA promise to lower its cost and widen its packaging applications, to include food packaging . PLA can be fabricated on a variety of familiar processes . There is a need to better understand its behavior and properties to be fully adapted in packaging applications.

19 Scheme 1 : Generalized flow sheet for the production of PLA from agricultural waste. 

20

21

22

23

24

25

26 Synthesis of Polylactic acid over
Solid acid catalyst

27 Characterization of Polylactic acid :
Experimental Section Lactic acid (LA) is a 85% aqueous solution of the monomer Catalyst Tungastophosphoric acid H3 [ P(W3O10) 4 ] x H2O (HPA) is heated at 1500C for 3 hours. The following products were used without any further treatment Chloroform-d1 with TMS (1%) (deuteration degree not less than 99.5%) from Merck for NMR measurements. Characterization of Polylactic acid : IR, TGA, DSC 13C NMR and GPC

28 Schematic Representation
10 gms of Lactic Acid 40 mg of HPA H3 [ P(W3O10) 4 ] Vessel with Dean Stark Trap Continuous flow of N2 Stirred at 1500C for 3 hrs Viscous liqiud Poured into 100ml of methanol Precipitate Filterd & Dried PLA

29 Experimental set up for the synthesis of polylactic acid
Dean stark trap Water removed through dean stark trap Continuous purging of N2 gas

30 Infrared Spectral Analysis of PLA
-C=O -C-O 1759 1092

31 13C NMR Analysis of PLA CDCl3

32 13C NMR Analysis of PLA δ 169.5 ( δ 69.0 ( O=C O C H-) δ 16.6 (
CDCl3 13C NMR of PLA ( Solvent CDCl3) δ ( δ ( O=C O C H-) δ ( C=O ) CH3 )

33 Thermo Gravimetric Analysis of PLA
PLA prepared at 1500C

34 Differential Scanning Calorimetric Analysis of PLA
Tg = 560 C Tm = 1300C

35 Thermo Gravimetric Analysis of PLA prepared at 1800C

36 Gel Permeation Chromatography Analysis
Wt Molecular weight

37 Polymerization of lactic acid by using various catalysts

38 Comparison with conventional catalyst
Temperature (0C) Mw(g/mol) GPC H2SO4* (Conventional) HPW# 180 200 220 150 31000 30600 32600 42496 * reaction duration -12 h # reaction duration -3 h

39 Condensation polymerization
Table 1 Summary of the catalysts used for polymerization of Lactic acid Condensation polymerization S.No Catalyst Weight % of catalysts Temp K MW(g/mol) 1 2 3 4 5 6 Tolune sulphonic acid Sulphuric acid Boric acid Phosphoric acid Nafion-H Methyl sulphonic acid 1,2.5 0.1to 1.5,2.5 0.1,2.5 2.0 2.5 ,403 373,403 453,473, 433 403 1458 100000 31000,65000 3800,6500 4000 20000

40 Ringopening polymerization
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 ZnCl2 Al(acac) Sn(II)octoate Sb2O3 Ti(IV)butylate Ti(IV)isopropylate Dibutyltin dilaurate (DBTL) Stannous octoate Tetraphenyltin Mg Al Zn Sn TiO2 ZnO GeO2 ZrO2 SnO SnCl2 SnCl4 Mn(AcO)2 Fe2(LA)3 Co(AcO)2 Ni (AcO)2 Cu (AcO)2 Zn(LA)2 Y(OA)3 Al(iPrO)3 Ti (BuO)4 TiO(acac)2 (Bu)2SnO 0.1 0.05 0.01 0.5 0.83 0.62 0.72 0.68 0.57 0.80 1.10 1.57 1.70 1.50 1.51 2.75 1.86 2.92 3.79 3.55 2.74 1.05 353 451 433 403 4700 3600 8000 10800 15000 9000 6700 ,000 ,000 2100 5400 35000 230000 1600 20000 1300 1500 29000 19000 27000 32000 1900 7000 13000

41 Table .2. Typical applications of PLA
Processes End Products Non woven fibres Personal hygiene, protective clothing, filtration Oriented films Container labels, tape Extrusion coatings Dinnerware, food packaging, mulch film Flexible film Food wrap, trash bags, shrink wrap Cast sheet Delivery trays Injection moulding Rigid containers, Dairy containers foam Clam shells, meat trays

42 Salient features Developed process utilizes a noncorrosive, environmentally friendly Solid acid catalyst The reaction temperature is decreased from 1800C to 1500C The reaction duration is three hours – obtained required Molecular weight The solid acid can be completely recovered and regenerated. The physico-chemical properties of PLA can be widely tunned according to the requirements i.e by changing various solid acid strength

43


Download ppt "Synthesis of Polylactic acid"

Similar presentations


Ads by Google