| The content of the thesis covers two parts.One is the synthesis and characterization of the aminopyridinium salts and their antimicrobial mechanism in the finishing of wool,nylon,acrylic,and cotton fabrics.The other is the synthesis and the antimicrobial efficacy of the antimicrobial cationic reactive dye and its performance in the dyeing of cotton,nylon,wool,and acrylic fibers.In foreword the background of topic selection of the thesis is described.In chapter 1 the recent progress in the world of studies on the antimicrobial finishing of textiles is introduced.The research works of the antimicrobial pyridinium salts and the antimicrobial dyes are majorly mentioned.In chapter 2 the research work is about the synthesis and characterization of the antimicrobial aminopyridinium salts with different alkyl chain length.As an effort to develop antimicrobial surface treatment agents for wool fibers,three antimicrobial 4-aminopyridinium salts were synthesized by using two different processes.The structures of the salts were fully characterized by using FT-IR,1~H-NMR and (13)~C-NMR analysis.Besides,their thermal stability was also conducted by using DSC and TGA.The yields of two synthesis processes were also compared.The antimicrobial efficacy of these compounds was evaluated by using a minimum inhibitory concentration(MIC)as an indicator.All of the synthesized aminopyridinium salts showed antimicrobial activities against gram-negative bacterium,but in different levels depending on their structures.The salts possessing longer alkyl chain length demonstrated better antimicrobial functions.The research result provided the theory and method guidance for the synthesis of novel antimicrobial quaternary ammonium salts.In chapter 3 the synthesized quaternary aminopyridinium salts were employed in antimicrobial finishing wool fabrics.All the finished wool fabrics exhibited antimicrobial efficacy against E coli.The quaternary ammonium salts could form ionic interactions with anionic groups on wool,which contribute to durable antimicrobial functions.The effects of alkyl chain length in the salts,pH conditions of finishing baths,finishing time and temperature,and salt concentrations were investigated.The absorption rate and the exhaustion percent of salts on the fibers were also measured.The incorporated quaternary aminopyridinium salt molecules on wool were characterized by FT-IR.The salt with the longest alkyl chain(12-C)showed the best antimicrobial performance and the washing durability of antimicrobial functions on the finished wool fabrics.The research provided a kinetics model for the antimicrobial finishing of wool fibers,acrylic fibers,and nylon fibers with quaternary ammonium salts.And it also provided an theory guidance for designing and synthesizing of biocides with high antimicrobial efficacy.The antimicrobial mechanisms of the aminopyridinium salts are further explored in chapter 4 and chapter 5 for a comprehensive understanding of it. Based on the research works of chapter 2 and chapter 3,chapter 4 was aimed to explore the relationship between chemical structure and antimicrobial activities of quaternary ammonium salts,particularly the impact of hydrophobicity of the salts on antimicrobial functions.Four quaternary ammonium salts(QASs),i.e. 4-aminododecylpyridinium chloride,4-acetylaminododecylpyridinium chloride, 4-benzoylaminododecylpyridinium bromide,and 4-(1-Naphthoyl) aminododecylpyridinium bromide were employed in antimicrobial tests against both gram-negative and gram-positive bacteria,E coli and S aureus.These four QASs possess the same long alkyl chain but different hydrophobic group at the 4-amino groups.Antimicrobial activity of QASs was measured in liquid phases by growing bacterial cultures in the presence and absence of the QAS.The most hydrophobic compound exhibited the strongest antimicrobial activity than other salts.All of the quaternary pyridinium salts exhibited significantly antimicrobial activities but in different extents according to their hydrophobicity at the 4-amino position.QASs which have larger hydrophobic groups were significantly more effective than that with smaller groups.This research revealed that hydrophobic and aromatic ring structures at 4-amino position on quaternary aminopyridinium ring could improve antimicrobial activity of the salts.The results could assist understanding and development of antimicrobial quaternary ammonium salts.Besides,the ionic bounds between the dyes and the salts could increase the antimicrobial durability of pyridinium salts.In chapter 5,three quaternary ammonium salts,namely 4-amino-laurylpyridium chloride(ALPC),4-benzoylamino-1-dodecylpyridinium bromide(BADPB),and 4-(l-naphthoyl)amino-l-dodecylpyridinium bromide(NADPB)were employed in antimicrobial finishing of cotton fabrics.The intermolecular interactions between the dyes and the aminopyridinium salts and their impact on the exhaustions of salts on the direct and reactive dyed fabrics were discussed.The quaternary ammonium salts could form ionic forces with sulfonate groups on the dyed cotton fibers,which contribute to higher exhaustion uptakes of the salts and better antimicrobial activities against E coli and and S aureus of the dyed cotton fabrics compared to that of the undyed sample.The fabrics also exhibited antimicrobial durability.The characteristics of chemical structure,antimicrobial activities,and the absorption performance on fibers of antimicrobial quaternary ammoniumsalts were finally obtained through the work recounted in the previous four chapters,which settles firm bases for the foundation of the antimicrobial cationic reactive dye.Based on these works,the major work introduced in chapter 6 was the synthesis, characterization,and antimicrobial activity of the cationic reactive dye. Anthraquinone ring was selected as a major chromophore to connect with quaternary ammonium structures because it is structurally small and widely available in different derivatives and has good chemical stability.The reactive group is three chloride triazine.The chemical structure of the new dye was fully characterized by using 1~H-NMR,(13)~C-NMR and FT-IR analyses.The color features of the dyes were studied in terms ofλmax andεmax in aqueous solutions,and the antimicrobial efficacy of the dye was evaluated by using the minimum inhibitory concentration(MIC)as an indicator.Differential scanning calorimetry(DSC)and thermogravimetric analysis (TGA)were employed in the studying of thermal stabilities.The results showed that a novel antimicrobial cationic reactive dye could be synthesized by following the designed procedure.The hydrophobic group of anthroquinone and triazine can improve the antimicrobial activities of the dye compared to the traditional salts.In chapter 7,the performance of the dye in the dyeing of cotton,nylon,wool,and acrylic fibers were investigated.The research focused on the effect of electrolyte concentration,dyeing time,and dyeing temperature to exhaustion and fixation of the cationic reactive dye on cotton fibers.It was found that the cationic reactive dye exhibited higher exhaustion and fixation values under free salt dyeing condition. Simultaneously,all the treated cotton fabrics exhibited antimicrobial efficacy against E coli and S aureus and showed promising durability fastness to washing.Besides,the cationic reactive dye could be introduced into wool,acrylic,and nylon fabrics by following traditional cationic dyeing procedures.All the treated fabrics exhibited antimicrobial efficacy against E coli and S aureus.To sum up,based on the synthesis and application of pyridinium salts,the synthesized novel antimicrobial cationic reactive dye combines the color and function together through suitable chemical linkages.The dye exhibits high affinity to the common fibers and the simultaneous dyeing and finishing can be achieved by simply following the traditional dyeing mechanisms.It is now possible to predict the salt free dyeing of reactive dye and realize the dyeing of multifiber fabrics with one kind of dye. |
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