| Sodium styrenesulfonate (SSS) was grafted onto polypropylene (PP) non-wovenfabric via60Co γ-ray simultaneous radiation grafting method with the addition ofN-vinyl-2-pyrrolidone (NVP), acryl amide (AAm) and acrylic acid (AAc),respectively. The sulfonated PP non-woven fabrics were characterized and theirproperties, including hydrophilicity, blood compatibility, anticoagulant effect andadsorption properties of low density lipoprotein (LDL), were evaluated.1. Preparation of sulfonated PP non-woven fabric via simultaneous radiationinduced graft copolymerizationIn this paper, we systematically studied the effect of absorbed dose, dose rate,total molar concentration and molar concentration ratio of binary monomers on theDGTand DGSSS, respectively. The results showed that different DGTand DGSSScouldbe attained by adjustment of the above parameters.2. CharacterizationAttenuated total reflection Fourier transform infrared spectroscopy: As comparedwith the spectrum of pristine PP non-woven fabric, the new bands at about1125,1039,and1009cm-1in the spectra of sulfonated PP non-woven fabrics inculdingPP-g-P(NVP-co-SSS), PP-g-P(AAm-co-SSS) and PP-g-P(AAc-co-SSS), belonged tosulfonate group (-SO3-). Besides, the peaks at about1673,1667and1715cm-1couldbe assigned to the stretching vibration of C=O from NVP, AAm and AAc,respectively. X-ray photoelectron spectroscopy: A fresh peak at168eV (S2p) appeared in the spectra of sulfonated PP non-woven fabrics. The intensity of O1s (531eV) peak of sulfonated PP non-woven fabrics was stronger than that of neat PPnon-woven fabric. Moreover, an original peak at399eV (N1s) emerged in the spectraof PP-g-P(NVP-co-SSS) and PP-g-P(AAm-co-SSS) samples. Suface morphology ofPP non-woven fabrics: According to the picture of scan electron microscope, thediameter of modified fibers was apparently larger than that of virgin fiber. Besides,the configuration of modified fibres seemed to be more compacted. Hydrophilicity:The consequence of adsorption percentage of deionized water and phosphate buffersolution (PBS)(pH,7.4) demonstrated that the sulfonated PP non-woven fabrics hadexcellent hydrophilicity.3. Blood compatibilityHemolysis: The hemolytic ratio of sulfonated PP non-woven fabrics was below5%, which met what the medical materials required. Adsorption density of BSA: Theadsorption density of BSA decreased with the increase of DG. Furthermore, the groupof PP-g-P(AAm-co-SSS) samples was more effective to resist the BSA adsorptionthan the other two groups. Adsorption density of total protein: The group ofPP-g-P(AAm-co-SSS) samples was more efficient to limit the total protein adsorptionthan the other two groups. However, the PP-g-P(AAc-co-SSS) samples showed moreattraction to total protein and the DG had little effect on the adsorption density.Number of adhered platelets: The amount of adhered platelets reduced with theraising of DG, and PP-g-P(AAm-co-SSS) samples were more proficient in restrictingthe adhesion of platelets than the other two group of samples. Morphology of adheredplatelets: A lot of platelets aggregated and adhered onto virgin PP non-woven fabric.The deposited platelets exhibited an activated morphology, as demonstrated byextended pseudopodia and surface spreading. On the contrary, there’s few plateletsadhered and aggregated on the surface of sulfonated PP non-woven fabrics, whichillustrated that sulfonated PP non-woven fabrics could effectively restrict the adhesionof platelets. The above results demonstrated that the hemocompatibility of PPnon-woven fabric was greatly improved after modfication. 4. Anticoagulant effectWe evaluated the anticoagulant effect of sulfonated PP non-woven fabrics viaexamination of clotting times, including activated partial thromboplastin time (APTT),prothrombin time (PT) and thrombin time (TT). The results proved that sulfonategroup showed good anticoagulative activity, especially lengthening the APTT(intrinsic coagulant pathway). Besides, the carboxyl group had a synergetic effect toextend the clotting time. However, the amide group did not indicate this kind ofeffect.5. Adsorption properties of LDLIn this paper, we assessed the selectivity of adsorbing LDL of sulfonated PPnon-woven fabrics by means of determination of adsorption percentage of LDL andhigh density lipoprotein (HDL). The prepared sulfonated PP non-woven fabrics, to acentain degree, presented the property of adsorbing LDL. However, the sulfonated PPnon-woven fabrics also showed adsorbing effect on HDL. Hence, the sulfonated PPnon-woven fabrics did not show good selectivity to adsorbing LDL, which should beameliorated in order to reduce the adsorption percentage of HDL and enhance theselective property of adsorbing LDL. |
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