(1. School of Materials Science, South China University of Technology, Guangzhou 510640; 2. Guangzhou Qingtian New Material Research and Development Co., Ltd., Guangzhou 510300) Polypropylene with antibacterial properties. Scanning electron microscopy showed that the surface-treated antibacterial particles were well dispersed in polypropylene, uniform in size, and had good compatibility with PP matrix; DSC test showed that antibacterial particles had heterogeneous nucleation-induced crystallization on PP matrix, which caused PP to crystallize. The increase of temperature and the increase of melting temperature. The addition of antibacterial particles will decrease the mechanical properties of polypropylene. However, the surface treatment of antibacterial particles and the change of fiber drafting ratio can reduce the decrease of the antibacterial properties of acrylonitrile, which is equivalent to that of ordinary propane. Through the detection of antibacterial properties of antimicrobial polypropylene, the antibacterial theory has strong antibacterial activity against gram-negative bacteria and positive bacteria. The antibacterial rate exceeds 99.9%. The antibacterial performance of antibacterial polypropylene is not greatly reduced by washing, and it has long Effective antibacterial properties.
Guan Yu Ci: Antibacterial Polypropylene Polypropylene Polypropylene Inorganic Antibacterial Agent. Foreword With the increasing production of human activities, especially the degree of industrialization, environmental pollution has become more and more serious. At the same time, people's awareness of environmental health and self-care has also been increasing, so various environmental protection materials and functional materials have emerged. In daily life, people are inevitably exposed to a variety of bacteria, fungi and other microorganisms. Under suitable external conditions, these microorganisms will rapidly multiply and spread diseases through contact, affecting people’s health and normal conditions. Work, study and life. Various kinds of textiles are often good habitats for these microbes and become an important source of transmission of diseases. Especially in hospitals, various contaminating bacteria are often floating in the air. There is a great possibility of bacterial contamination on the clothing of hospital staff and patients, as well as textiles for bedclothes, curtains, carpets and other hospitals. This is not only prone to cause cross-infection of patients, but also spreads germs to healthy people and to hospitals. Outside environment. Therefore, the research and development of antibacterial properties of textiles is of great importance. Antibacterial fibers are greatly appreciated by consumers because of their function of blocking disease transmission, health cleaning, and maintenance of their own performance.
Polypropylene fiber has the advantages of good moisture-conducting property, good hygienic property, low price, etc. The application range is expanding day by day, especially in the fields of medical and health care. Polypropylene itself has good mold resistance, but various additives and oils need to be added during the spinning process. Therefore, under the appropriate conditions of temperature and humidity, microorganisms will adhere to the fibers. Therefore, research and development of antibacterial properties Polypropylene fiber has attracted the interest of researchers at home and abroad.
In order to prepare long-acting, broad-spectrum antibacterial, safe and non-toxic antibacterial fibers that have little effect on the original properties of the fiber, a high-efficiency, low-toxicity, broad-spectrum, heat-stable inorganic antibacterial agent and polypropylene fiber were selected for the study. The polymers were melt-blended and blended to develop a fiber with long-lasting antibacterial activity. The dispersion of the antibacterial agent in the fiber and its effect on the physical structure and mechanical properties of the polypropylene were studied.
1. As shown in (b), surface-treated antibacterial powders greatly reduce the interaction forces between particles and reduce the secondary agglomeration of particles, resulting in better dispersion and comparison in polypropylene. Because of the small particle size, white spots in (a) do not occur.
(c), (d) It can be seen that the interface between the antibacterial particles without surface treatment and the matrix resin has a clear interface between the two phases, and the particles are partially exposed on the surface, both of which show the interface incompatibility of the surface, and the surface-treated ones. The antibacterial particles have good compatibility with the matrix resin, and the particles are substantially completely embedded in the matrix resin. The interface between the two is continuous and there is no phase separation phenomenon. It can be seen that surface treatment of antibacterial particles not only improves the dispersion of the particles in the matrix resin, prevents particle agglomeration and reduces the particle size, but also enhances the compatibility of the particles with the matrix tree i, and promotes the interfacial Adhesion, which played a significant role in improving the mechanical properties of antimicrobial polypropylene.
2.2 The effect of antibacterial particles on the crystalline structure of polypropylene The looted yellow line (upper curve) represents antimicrobial polypropylene; the lime line (below the curve) represents the DSC curve of polypropylene antimicrobial polypropylene. It is known that adding 1% of antibacterial powder, melting temperature of I> P ( Tm) has improved. Moreover, the exothermic peak of the antibacterial PP is narrow and the exothermic peak area increases, which indicates that the antimicrobial PP has a more complete crystal structure and higher crystallinity.
This is attributed to the heterogeneous nucleation-induced crystallization of the inorganic antimicrobial particles in the PP matrix. The surface modification improves the compatibility of the polar inorganic antimicrobial particles with the non-polar PP, facilitates the contact between the inorganic antimicrobial particles and the PP matrix, activates the nucleation sites of the antimicrobial particles, increases the induced nucleation sites, and increases the crystallinity. The crystal size is reduced and the structure is more complete.
2.3 Influence of Antibacterial Particles on the Mechanical Properties of Polypropylene 2.3.1 Effect of Draft Ratio on the Mechanical Properties of Polypropylene The antibacterial PP has low primary fiber strength and large elongation. It does not meet the requirements for use. It requires post-draft to improve the mechanical properties of the fiber. The mechanical properties of antibacterial PP primary fibers at different draw ratios are shown. The breaking strength of blank PP fiber and antibacterial PP fiber increased with the increase of draw ratio, and the elongation at break decreased. At the same draw ratio, the breaking strength of the antibacterial PP fiber is slightly lower than that of the blank PP fiber. This is because the antibacterial particle is an inorganic rigid particle, although the surface treatment improves its compatibility with the PP matrix, but this It is not possible to make the two completely compatible. Therefore, under the effect of stress at the interface where the compatibility between them is slightly poor, they are first destroyed and become the starting point of the overall performance destruction of the material, and the mechanical properties of the material are rapidly reduced. In addition, some particles with larger particle size in the antibacterial particles also cause the structural properties of the material to decrease. The elongation at break of antibacterial PP fiber is higher than that of blank PP fiber. It may be that the low-molecular wax added in the antibacterial masterbatch plays a plasticizing role in the matrix, which improves the ability of the PP molecular chain to move, and the draft ratio increases. The larger the fiber denier, the quicker the plasticization, and the greater the elongation at break.
As can be seen from the figure, when the draft ratio exceeds 7 times, the breaking strength of the antibacterial PP fiber exceeds 4 cN/dtex. After 8 times of drafting, both the breaking strength and the breaking elongation are similar, therefore, Without reducing the other properties, the breaking strength of the antibacterial fiber can be increased by increasing the draw ratio, and the elongation at break can be reduced to meet the practical application requirements.
Since antibacterial fiber is mainly used for the production of underwear and hosiery, the strength of the fiber is also an important performance. As shown, the antibacterial fiber collapsing strength increases as the draft multiple increases, and the collapsing elongation at break gradually decreases. This is similar to the change in tensile breaking strength and elongation. But both are generally higher than blank PP fibers. Comparison data shows that when the draw ratio is 8 times, the mechanical properties of the antibacterial fiber are the best. Therefore, studying the mechanical properties of antibacterial fibers at different draw ratios is of great significance for antibacterial PP fibers with excellent textile properties.
2.3.2 Addition of anti-mowing masterbatch to children's mechanical properties of polypropylene The content of antibacterial particles (cN/dtex) breaking elongation ratio: 4 can be seen from Table 1, with the increase in the amount of antibacterial powder added, in Under low draw ratio conditions, there is no significant change. When the draw ratio increases, the breaking strength of the fiber decreases, and the elongation at break decreases under different draw ratio conditions. This is due to the addition of antibacterial particles, which affects the high The regularity of the molecules and the intermolecular attraction, especially when the amount of particles increases and the distribution is uneven, the fibers are easily broken at the sites where the antibacterial particles are concentrated, and the physical and mechanical properties of the fibers are reduced. Therefore, the size of the antibacterial particles must be strictly controlled and uniform. Degree of dispersion in the fiber, and in ensuring the antibacterial properties, while minimizing the amount.
2.4 Anti-seedling properties of anti-miao polypropylene Table 2. Antibacterial properties of antibacterial C to E. coli and Staphylococcus aureus Initial bacterial colonies of the strain (cfu/m) Number of surviving colonies after 24 hours (cfu/m) Bactericidal rate Antibacterial Activity value E. coli antibacterial polypropylene blank polypropylene control Staphylococcus aureus antibacterial polypropylene blank. The polypropylene control sample showed that the antibacterial agent had excellent antibacterial activity against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli), and the antibacterial rate reached more than 99.9%. The antibacterial activity values ​​are far more than 2.0. It can be seen that the antibacterial polypropylene has a strong bactericidal and antibacterial effect.
(Antibacterial fiber dose 100mg/ml, l blank; 2 antibacterial fiber; 3 antibacterial fiber after washing) Antimicrobial properties after antibacterial polypropylene washing are shown. After 6 hours of boiling water treatment, a small part of the surface of the fiber is released from the fiber surface, which will reduce the antibacterial properties of the polypropylene fiber, but the internal deep particles will slowly migrate to the surface of the fiber under the impetus of the poor concentration, so that the antibacterial ability will be obtained. Addition, so that the decline in the antibacterial properties of the fiber is not large, the fiber still has good antibacterial properties, it is for this reason, this antibacterial fiber has long-lasting antibacterial properties.
3 Conclusion Surface treated antibacterial particles dispersed well in polypropylene, and has good compatibility with PP matrix.
By changing the draft ratio, antibacterial PP fibers with excellent properties can be obtained, and their mechanical properties are comparable to ordinary polypropylene.
Antibacterial particles have a heterogeneous nucleation effect on PP, which increases the crystallinity of PP and increases the melting temperature (Tm).
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