Elastomer surface energy modification applying oxygen and nitrogen plasma treatment with laser deactivation of the surface

doctoral thesis

• Author: Gorazd Golob
• Mentor: Mladen Lovreček (mentor)
• Committee member: Stanislav Bolanča (član povjerenstva)
• Committee member: Mladen Lovreček (član povjerenstva)
• Committee member: Miran Mozetič (član povjerenstva)
• Committee member: Marta Klanjšek Gunde (član povjerenstva)
• Committee member: Vesna Džimbeg-Malčić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Graphic Arts; Zagreb
• Defense date and country: 2011-00-00, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Graphic Technology
• Universal decimal classification (UDC): 655 - Graphic industries. Printing. Publishing. Book trade

Abstract

Cilj doktorske teze je istraživanje površinske slobodne energije, hrapavosti i drugih

svojstva površine NBR i EPDM ofsetnih “gumenih navlaka“, funkcionalizacija

površinskih svojstva obradom pomoću kisikove i dušikove plazme te

defunkcionalizacija površine primjenom IR i UV lasera. Karakterizacija površinske

slobodne energije mjerenjem kontaktnog kuta primjenom testnih tekućina sa različitom

površinskom napetošću i polarnošću, SEM (skenirna elektronska mikroskopija), XPS

(spektroskopija rendgenskim zrakama) i analiza hrapavosti ispitivanih elastomera i

njihovih komponenti, daje kvantitativni opis za plazmu specifičnih površinskih

funkcionalnih grupa, koje su u korelaciji s površinskom energijom, polarnošću i drugim

površinskim svojstvima spomenutih materijala, tako da se mogu procijeniti promjene

adsorpcijskog potencijala, odnosno njegova hidrofilna/oleofobna ili hidrofobna/

oleofilna svojstva.

Kemijska analiza površine elastomera (“gumene navlake“) nakon obrade plazmom i

laserom, u usporedbi sa neobrađenim uzorcima, pokazuje velike promjene samo kod

sumpora, koji je korišten za vulkanizaciju. Druge, manje vidljive promjene u kemijskoj

strukturi nastale su zbog kemijskih reakcija čestica plazme sa silika punilom ili sa

dodacima, radije nego sa osnovnom makromolekularnom strukturom elastomera. Kod

nevulkanizirane sirove gume nema vidljivih kemijskih promjena nakon obrade

kisikovom plazmom ili UV laserom, uz istovremene značajne promjene površinske

slobodne energije i polarnosti. Kod sirove gume promjene su uzrokovane promjenom

makromolekularne strukture površine.

“Gumena navlaka“ dobro je poznati medij za prijenos tiskarske boje u ofsetnom i

drugim konvencionalnim i digitalnim tiskarskim tehnikama, gdje djeluje kao

sekundarna tiskovna forma. Zapisivanje na površinu “gumene navlake“ pomoču obrade

plazmom i laserom za selektivnu defunkcionalizaciju, otvara nove mogučnosti u

njezinoj upotrebi o ulogi nosioca slike u tiskovnom procesu i time novi izazov za

buduča istraživanja.

Abstract (english)

The aim of the thesis was to investigate the surface free energy, roughness and other

surface properties of NBR and EPDM lithographic offset “rubber blankets“, to

functionalize the surface properties with an oxygen and nitrogen plasma treatment, and

to defunctionalize the surface by applying IR and UV lasers. The characterization of the

surface free energy with contact angle measurements using test liquids with different

surface tension and polarity, SEM (scanning electron microscopy), XPS (X-ray

photoelectron spectroscopy), and roughness analysis of the investigated elastomers and

their components provided a description of specific surface functional groups that are in

correlation with the surface free energy, polarity and other surface characteristics of

elastomers. Therefore, their adsorption potential changes and their hydrophilic/

oleophilic or hydrophobic/oleophobic properties can indirectly be evaluated.

The chemical analysis of the surface of elastomer (“rubber blanket“) after the plasma

and laser treatment, compared to the untreated samples, showed significant changes

only in sulphur used as the curing agent. Other, less significant changes in the chemical

composition occurred due to the chemical reactions of plasma species with the silica

filler or additives, rather than with the basic macromolecular structure of the elastomer.

With the uncured crude rubbers, there were no apparent chemical changes after the

oxygen plasma or UV laser treatment, while there were simultaneously significant

changes in the surface free energy and polarity. With crude rubber, the changes took

place due to the changes in the macromolecular structure of the surface.

“Rubber blanket“ is a well-known ink transfer media in lithographic offset and other

conventional or digital printing techniques, where it is used as the secondary printing

forme. The rendering of the “rubber blanket“ surface by using a plasma and laser

treatment for a selective defunctionalization is opening new possibilities in using the

“rubber blanket“ as an image carrier in the printing process and thus offers a new

challenge for future research.

• Keywords: elastomer; ofsetna gumena navlaka; plazma; površinska slobodna energija; laser
• Keywords (english): elastomer; offset rubber blanket; plasma; surface free energy; laser
• Language: croatian
• URN:NBN: urn:nbn:hr:216:443916
• Study programme: Title: Graphic engineering and graphic product design; Course: Graphic technology; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti u području tehničkih znanosti (doktor/doktorica znanosti u području tehničkih znanosti)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-04-24 22:42:53