SYNTHESIS AND CHARACTERIZATION OF PP FILMS RICH IN PRIMARY AMINES FOR CELL CULTURES, BY GAMMA RADIATION

Mitzi P. Pérez-Calixto*Guillermina Burillo

*mitzi.perez@correo.nucleares.unam.mxInstituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito exterior,

Ciudad Universitaria, México D.F. 04510, MéxicoInternational Conference on Applications of Radiation Science and Technology

(ICARST 2017)24 to 28 April 2017, Vienna, Austria

• INTRODUCTION

Development of biomaterials are very important for tissue engineering.They can be used as bridges to regenerate damaged tissue growth, as wellas support for immobilized biomolecules (drugs, enzymes, etc.). Polymersurface modification can be carry out by incorporating functional groups onpolymeric materials for the appropriate cell adhesion. It is well known thathydrophobic polymeric surfaces cannot add cells, however, hydrophilicsurfaces, mainly those reach in amine functional groups (-NH2) facilitate celladhesion.

One of the methods used to modifier surfaces is by plasma, even though isthe more common, the systems synthesized are partly soluble in water,besides the formation of a great amount of free radicals, which generate theincorporation of oxygen when is in contact with the air. To overcome thisproblem, the modified films were synthesized by gamma radiation. In thiswork, radiation grafting of acryloyl chloride onto polypropylene (PP) hasbeen applied to insert carboxyl functionalities on PP; and then, the radiationgrafted films were reacted with some diamines. Amine concentration wasdetermined and after a period of time, the effect of aging on the aminefunctional groups was determined by derivatization with 4-trifluoromethylbenzaldehyde (TFBA), and subsequently characterized by XPS ( N/N/Cratios), ATR-FTIR, AFM, SEM and contact angle.

SEM

esterificationreaction

Radiation γDirect MethodeI: 5 kGy/h

AC graft

Polypropilene(PP)

Aminolysisreaction

Chemicalderivatizati

on withTFBA

Characterization

FTIR-ATRAFM XPSContactangle

Determination of graftpercentage:

G(%)=𝑊𝑔−𝑊0

𝑊𝑜

Where W0 y Wg is theweight before andafter being grafted

• EXPERIMENTAL

• RESULTS

• CONCLUSIONS

(FTIR-ATR)

AcknowledgementsThe authors thanks to M. Cruz, and A. Ortega for technical support andDGAPA UNAM Grant IN200116 for financial support.

XPS

Atomic Force Microscope

Contact angle

Fig. 3. Average Roughness of a) PP film: 10.54 nm. Surface area: 100.25 µm b) PP-g-EAAm:45.25nm. Surface area : 102.54 µm2

Elemental Composition (At. %)

C1s O1s N1s Cl 1s F1s Si2p

a) PP 85.5 10.5 ----- <0.1 4.0

b) PP-g-MA 59.4 37.4 --- 0.5 2.7

d) PP-g-EAAm

+TFBA79.1 10.3 5.7 ---- 3.0 1.9

0 2 4 6 8 100

40

80

120

160

200

Gra

ft (

%)

Dose(kGy)

+

ACPP PP-g-AC

Aminolysis reactionEsterification reaction

SEM

Fig.2. FTIR of different systems: a) PP film; b) PP-g-MA; c) PP-g-EAAm; d) derivatized with TFBA

a)

b)

Fig.4. SEM photomicrographs of cross-section (a) PP films; and (b) PP-g-EAAm.

(a) (b)

Fig.5 Contact angle of (a) PP films 91.1±0.29; and (b) PP-g-EAAm. : 73.4 ± 1.37

(a) (b)

Fig. 1 Grafting percentage of AC as a function of dose. [AC: ]50% v/v toluene

800 600 400 200 0

N 1s

C1s

C1s

C 1s

O 1s

O 1s

O 1s

PP-g-EAAm+TFBA

PP-g-EAAm

PP-g-MA

Si 2pSi 2s

Si 2sSi 2p

Si 2pSi 2s

Binding Energy (eV))

Inte

nsity (

a. u.) Cl 2p

Si 2s

N 1sO 1s

F 1s

Si 2p

PP

C1s

4000 3500 3000 2500 2000 1500 1000

N-H

amine

-C-H

alifatic

(d)

(c)

(b)

Tra

nsm

ittance

(u.a

.)

Wave length (cm-1)

(a)

-C-H

alifatic

-C=O

ester

O-CH3

methyl ester

N-H

amine

-C=O

amide

aromatic

C=N

imine

It is possible to modify the surface of PP films with ethylene diamine by the technique ofgamma radiation (direct method), by different steps of synthesis. Films with more than 100%grafting were chosen because better yields were obtained in the subsequent reactions. Themodified system was characterized by the FTIR-ATR, AFM, SEM and contact angle techniques,which confirmed the grafting, surface roughness and hydrophilicity modification; thosemodification are requirements for cell adhesion. The elemental composition by the study of XPSshows that primary surface amines are present. The proposed synthetic technique makes itsuitable for cell adhesion, without presenting the disadvantages by plasma deposition.

PA2-38