i think these article will give you answer;
1.Interaction forces between cellulose microspheres and ultrathin
cellulose films monitored by colloidal probe microscopy?effect of wet
strength agents
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WHR-4D98H87-C&_user=1492102&_coverDate=01%2F01%2F2005&_alid=406020132&_rdoc=28&_fmt=full&_orig=search&_cdi=6857&_sort=d&_st=4&_docanchor=&view=f&_acct=C000053172&_version=1&_urlVersion=0&_userid=1492102&md5=b799fe1562db84607b959642e6b05b61
Colloidal probe microscopy was employed to study forces between
cellulose surfaces upon addition of a series of cationic copolymers in
aqueous solution, as model compounds for wet strength agents. The
content of quaternary ammonium groups and primary amines was
systematically varied in the cationic polymers, to distinguish between
the importance of electrostatical and H-bonding effects. Cellulose
microspheres were glued at the apex of tipless microfabricated
cantilevers and used as colloidal probes. Ultra thin cellulose films
and cellulose fibres were employed as model surfaces. The cellulose
films of a thickness of about 5 nm were spin-coated from cellulose
solution onto silicon substrates. The root-mean-square-roughness (RMS)
was 0.3?0.8 nm. The cationic model polymers were compared to
Servamine, a polymer employed as standard wet strength resin in
papermaking industries. Force versus separation measurements showed a
detailed picture of adhesion and contact breaking. Relatively strong
adhesion of the order of 0.3 mJ/m2 was observed with Servamine within
a range of approximately 10 nm. At larger distances weak bond breaking
and elastic chain pulling were identified. When approaching the
surface one to two small jump-in's possibly related to strong binding
of Servamine and subsequent attraction could be found in the case of
Servamine. In contrast, all the model copolymers showed only a weak
adhesion of 8?30 ?J/m2, i.e., an order of magnitude less than that of
Servamine and subsequent elastic rupture domains. The contour length,
persistence length and characteristic rupture distances were
calculated by means of applying the WLC model. Measurements against
cellulose fibres obtained from the production process proved the
relevance of the model systems.
2.Cellulose fiber/poly(ethylene-co-methacrylic acid) composites with
ionic interphase
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TWN-49HMTRN-1&_user=1492102&_coverDate=11%2F30%2F2003&_alid=406020132&_rdoc=41&_fmt=full&_orig=search&_cdi=5567&_sort=d&_st=4&_docanchor=&view=f&_acct=C000053172&_version=1&_urlVersion=0&_userid=1492102&md5=7c0436c29fd8f7786e569f3d10c835f9
Cellulose fiber/thermoplastic composites with ionic interphase were
prepared from modified cellulose fibers and
poly(ethylene-co-methacrylic acid) (PE-co-MA). The cellulose fiber was
treated by using coupling agent or sodium hydroxide followed by
introduction of ionic quaternary ammonium groups on the fiber surface,
which was then compounded with the polymer having anionic groups. The
effect of the ionic interface on the composite physical and thermal
dynamic properties was investigated. An obvious improvement in
mechanical strength of the ionic-interface composites was observed due
to acid?base interactions. The improved adhesion could be ascribed to
the interaction between cationic grafted groups at the cellulose fiber
surface and the anionic groups in the PE-co-MA. |
