Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers...

26
Radiation Modification of Natural Polymers Lecturer : Assoc. Prof. Dr. Murat Şen Hacettepe University Department of Chemistry, Polymer Chemistry Division, 06532, Beytepe, Ankara, TURKIYE 1

Transcript of Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers...

Page 1: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

Radiation Modification of Natural PolymersLecturer : Assoc. Prof. Dr. Murat Şen

Hacettepe University Department of Chemistry,Polymer Chemistry Division, 06532, Beytepe, Ankara, TURKIYE

1

Page 2: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

Topic: Radiation Modification of Natural Polymers

Major Processes For the Radiation Modification of Natural Polymers

Cross-linkingNatural rubber latex

Crosslinking of polysaccharides

DegradationCellulose fibers obtained from wood pulp

Degradation of polysaccharides

Preparation of blendsPreparation of synthetic-natural polymer blends

2

Page 3: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

Various research works have been performed on radiation vulcanization of natural rubber latex (RVNRL) since it possesses several advantages over sulfur vulcanization such as

Topic: Radiation Modification of Natural Polymers [1]

Polyfunctional monomers which contain more than two polymerizable C C double bonds in a molecule, and monofunctional acrylic monomers were used as vulcanization accelerators. Among the monofunctional monomers,n-butyl acrylate (n-BA) is the most effective vulcanization accelerator because it not only imparts much better physical properties at lower Dv but also unreactedn-BA is not retained in the final product

The low glass transition temperature of poly(n-BA) and a high probability of chain transfer reaction of n-BA during polymerization are closely related to its highsensitizing effect

the absence of nitrosoamines compoundsbetter transparency very low cytotoxicityand less rubber proteins that causes allergic response

Radiation vulcanization of natural rubber latex

3

Page 4: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

Many attempts were made to investigate an alternative accelerator to be used in radiation vulcanization of natural rubber latex (RVNRL)

Trimethylol propane tri-methacrylate (TMPTMA)Phenoxy polyethylene glycol acrylate(polyfunctional monomer) (PPEGA)Phenoxy ethyl acrylate (PEA),

Topic: Radiation Modification of Natural Polymers [2]

Variation of tensile strength of NR vs dose

Variation of tensile strength of RVNRL prepared using TMPTMA at various doses of radiation.

Gelation dose

4

Page 5: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

Topic: Radiation Modification of Natural Polymers [17]

Rayon is produced from viscose, a polymer made from cellulosic materials such as wood pulp

Cellulose fibers extracted from wood pulp can be converted to a thick liquid called viscose, which is used to make commercial products such as rayon fabrics and cellophane films.

The molecular weight of the natural cellulose is reduced by treatment with sodium hydroxide and heat. Then this material is dissolved in carbon disulfide to make viscose

Initial irradiation of the cellulose causes a reduction in molecular weight, and enables the rest of the process to be completed in less time with less chemical treatment

This reduces the cost and also reduces the environmental pollution. The dose requirement is about 15 kGy

VISCOSE - RAYON AND CELLOPHANE5

Page 6: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

Topic: Radiation Modification of Natural Polymers [16]6

Page 7: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

Topic: Radiation Modification of Natural Polymers

ALGINATESFood stabilizer, gelling agent, encapsulation matrix, plant growth stimulatorCARRAGEENANSFood processing, thickening agent, film forming, agriculture, horticulture, anti-HIV activitiesCHITOSANFood processing, paper and textile industries, photographic processing, biomedical applications due to antifungal, antibacterial, antitumor activities as well as immuno-enhancing effects and protective effects against infection

POLYSACCHARIDES

7

Page 8: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

OO

O

K

O3SO

OHO

CH2

OHO

OHOH2C

OO

OHO

OCH2 K O

OHO

CH2OHO3SO

Possible gelation mechanism of κ-carrageenan in aqueous solution: (----),ionic bonding; ( ), electrostatic forces of attraction.

Topic: Radiation Modification of Natural Polymers8

Page 9: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

• Gigartina (France, Argentina/Chili, Morocco) • Chondrus (France, North Atlantic) • Iridaea (Chili) • Eucheuma (Philippines/Indonesia)

Topic: Radiation Modification of Natural Polymers9

Page 10: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

• Natural polysaccharides from seaweeds (brown algae)

• Alginate is phycocolliod• Consists of linear chains composed of two

monosaccharides; – D-mannuronic acid (mannuronate) (M) – L-guluronic acid (guluronate) (G)

Topic: Radiation Modification of Natural Polymers

O

OOH

COONa

HO O

OHHO

COONa

OO

OH

O

-OOC

OHO

OH

COONa

OH

OO

O

-OOC

HO O

HO

COO-OH

OH

OO

OH

O

-OOC

OH

Sodium Alginate

D-guluronate (G) D-mannuronate (M)

O

COONa

O

OH

HO O

OH

COONa

HO

G G M M G

Sodium Alginate

10

Page 11: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

• Water-soluble gums sulfated polysaccharides

• 1,3 linked β-D- galactose and 1,4 linked α-D- galactose units.

• Anionic poly-electrolytes.• Three main branches.

– Kappa– Iota– Lambda

Topic: Radiation Modification of Natural Polymers

Carrageenans

O

OH

CH2OH-O3SO

O OO

OH

H2C

O

OCH2OSO3

-

-O3SO

O

-O3SO

CH2OHOH

O O

O

OSO3-

H2C

OOO

OH

CH2OH-O3SO

O

ι-carrageenan

λ-carrageenan

κ-carrageenan

11

Page 12: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

Topic: Radiation Modification of Natural Polymers

The most essential medical applications of chitosan are as follows - wound healing promoting dressings- dermatological agents- biodegradable carriers for slow release

drugs- anticoagulant agents- optimological, dentistical and orthopedic agents

- tumor cell metabolism reducing agents

Chitosan

It occurs in the shells of crabs, shrimps, prawns, lobsters, insects as well as some fungi wall cells.

12

Page 13: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

Topic: Radiation Modification of Natural Polymers

DEGRADATION OFPOLYSACCHARIDES

• Chemical• Microwave• Enzymatic• Photolysis• Ultrasound• Radiation

13

Page 14: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

• Radiation cause the breakage of glycosidic bonds

• Molecular weight, viscosity,gel strength decreases

• Alginates were irradiated as solid state or in aqueous solutions

RADIATION-INDUCED DEGRADATION OF ALGINATE

Topic: Radiation Modification of Natural Polymers14

Page 15: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

Alginate degradation under N2 and O2 conditions

Topic: Radiation Modification of Natural Polymers [3]15

Page 16: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

Color Change of Irradiated Alginate

Topic: Radiation Modification of Natural Polymers [3]16

Page 17: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

Appearance of mango treated with irradiated chitosan after 12 and 17 days storage

Fresh mangoes were dipped into the irradiated chitosan solution (1%) and dried for surface coating.

Topic: Radiation Modification of Natural Polymers [8]

Mango treated with irradiated chitosan

17

Page 18: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

Rice was cultivated for 9 days in hydroponic solution with 20

ppm alginate irradiated in 4% solution

Alginate was irradiated at 100 kGy in 4% solution and rice

was cultivated for 9 days

Effect of irradiated alginate on rice growth

Effect of concentration of degraded alginate

on rice growth

(1) Without alginate(2) (2) 20 ppm alginate irradiated (3) at100 kGy in 4% solution(3) 20 ppm alginate irradiated At 500kGy in solid state.

Growth of rice with alginate irradiated in liquid and dry

Topic: Radiation Modification of Natural Polymers [9]18

Page 19: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

Topic: Radiation Modification of Natural Polymers [9]

Effect of concentration of degraded alginate on peanut growth. Alginate was

irradiated at 100 kGy in 4% solutionand peanut was sprayed with alginate

solution for 15 days after 30 days cultivation

Change in net photosynthesis of peanut plant by foliar spraying of irradiated

alginate. : without alginate,

:sprayed with irradiated alginate.

Effect of degraded alginate on peanut growth

19

Page 20: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

Rice was cultivated for 9 days in hydroponicsolution with 100 mg/ml chitosan.

From left, (1); control (without chitosan), (2); with unirradiated chitosan,

(3)–(5); 20, 50 and 100 kGy-irradiated chitosan

Change in rice growth with treatment of irradiated

chitosan.

Topic: Radiation Modification of Natural Polymers [10]

Rice was cultivated for 9 days in hydroponic solution with

100 mg/ml chitosan

shoot; root; shoot without chitosanroot without chitosan.

Effect of irradiated chitosan for rice growth

Effect of radiation-degraded chitosan on plants stressed with vanadium

20

Page 21: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

Rice and soybean plants were damaged at 2.5 mg/ml V (in VCl3).

These damages were reduced by application of radiation-degraded chitosan.

Bioimaging analyzer system (BAS) images of 48V in rice under V stress (10 mg/ml) with 50 mg/ml of irradiated chitosan.

Left: with chitosan

right: without chitosan.

Topic: Radiation Modification of Natural Polymers [10]21

Page 22: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

Topic: Radiation Modification of Natural Polymers

New topics

A composite material for dietary applications

Microgel particles (swelling)

Radiation-modified chitosan (effective lipid+cholesterol binding)

Lipid+cholesterol binding

Synthetic biocompatible polymer Microgels

Matrix Fat-bindingagent

Action

Crosslinking

22

Page 23: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

New topics

Binding of lipids: ca. 20 g per 1 g of our composite substrate

Lipid + cholesterol binding

O

OH

NH3HO O

nClO4

Preliminary animal studies under way (with positive results).

0

1

2

3

4

5

6

7

8

1 2 3 4 5 6 7 8 9

0kGy10 kGy30 kGy

Fat binding

Topic: Radiation Modification of Natural Polymers23

Page 24: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

Polysaccharides undergo degradation by irradiation

Irradiation of polysaccharides at paste-like condition will led to crosslinking and form hydrogel.

Topic: Radiation Modification of Natural Polymers [11-12]24

Page 25: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

crosslinked CMC mat in the surgicaloperation room

CMC gel

plastic bag containingCMC gel,

Topic: Radiation Modification of Natural Polymers [13]

Crosslinked CMC is suitable for healthcare product such as surgical operation mats for prevention of bedsores

High viscous solution of 20% CMC was pressed into a plastic bag and irradiated with 10 kGy

commercialized as‘‘Non-bedsore’’ in Japan.

Such mats were tested by 68 patients in a hospital. No bedsores were observed in 64 patients andonly red spots appeared on 4 patients immediately aftersurgical operation

This result reveals that the crosslinkedCMC mat is extremely effective to prevent bedsores during surgical operation

This CMC gel mat is considered to disperse the body pressure and tomaintain the best circulation of blood during operation

25

Page 26: Radiation Modification of Natural Polymers · Topic: Radiation Modification of Natural Polymers [17] Rayon is produced from viscose, a polymer made from cellulosic materials such

Topic: Radiation Modification of Natural Polymers [14-16]

Preparation of synthetic-natural polymer blends

PVP-kappa carrageenan

PVP-agar

PVA-agar

Chitosan-grafted N-isopropylacrylamide

Chitosan/pHEMA membranes

Synthesis of antibacterial PVA/CM-chitosan blend hydrogels

26