(1. School of Materials, South China University of Technology, Guangzhou 510640; 2. Guangzhou Qingtian New Materials Research and Development Co., Ltd., Guangzhou 510300), which has antibacterial properties. Scanning electron microscopy showed that the surface-treated antibacterial particles dispersed well in polypropylene, uniform size and good compatibility with PP matrix. DSC test showed that antibacterial particles had heterogeneous nucleation induced crystallization on PP matrix, which made PP crystallize. The degree of increase and the melting temperature increase; the addition of antibacterial particles will reduce the mechanical properties of the polypropylene, but the surface treatment of the antibacterial particles and the change of the draw ratio of the fibers can reduce the decline in the performance of the antibacterial powder, making it comparable to ordinary C; Through the detection of antibacterial properties of antibacterial polypropylene, the antibacterial propagage has strong antibacterial activity against Gram-negative bacteria and positive bacteria, and the antibacterial rate exceeds 99.9%. The antibacterial performance of antibacterial polypropylene decreases little after washing, and has long Antibacterial properties.
Key words: antibacterial antibacterial polypropylene polypropylene polypropylene inorganic antibacterial agent. Foreword With the increasing production of human activities, especially the degree of industrialization, environmental pollution is becoming more and more serious, and people's awareness of environmental health and self-health is also increasing. Therefore, various environmentally friendly materials and functional materials have emerged. In daily life, people inevitably come into contact with a variety of microorganisms such as bacteria and fungi. Under appropriate external conditions, these microorganisms will rapidly multiply and spread diseases through contact, etc., affecting people's health and normal. Work, study and life. All kinds of textiles are often a good habitat for these microorganisms and become an important source of transmission for diseases. Especially in hospitals, various polluting bacteria are often floating in the air. Medical staff and patients' clothing, as well as bed linen, curtains, carpets and other hospitals, there is a great possibility of carrying bacteria on the textiles. This is not only easy to cause cross-infection of patients, but also to spread the bacteria to healthy people and to the hospital. Outside the environment. Therefore, the research and development of the antibacterial function of textiles is particularly important. Antibacterial fiber is greatly loved by consumers because of its blocking function of disease transmission, hygienic cleaning function, and maintenance function of its own performance.
Polypropylene fiber has the advantages of good moisture permeability, good hygienic performance and low price, and its application range is expanding day by day, especially in the fields of medical and health care. Polypropylene itself has good mold resistance, but it needs to add various additives and oils during the spinning process. Therefore, under appropriate temperature and humidity conditions, microorganisms will also 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 fiber with little influence on the original properties of the fiber, this study selected high-efficiency, low-toxic, broad-spectrum, thermal stability and good inorganic antibacterial agent and polypropylene fiber. The polymer was melt blended and developed into a fiber with long-lasting antibacterial function, and the dispersion of the antibacterial agent in the fiber and its influence on the physical structure and mechanical properties of the polypropylene were studied.
1. As shown in (b), the surface-treated antibacterial powder greatly reduces the interaction force between the particles, reduces the secondary agglomeration of the particles, and makes them have better dispersibility in the polypropylene. The small particle size, so the white spot phenomenon in (a) did not appear.
(c), (d) can be seen 5, the surface of the two-phase antibacterial particles and the matrix resin are clear, the particles are partially exposed on the surface, and the two exhibit the interface incompatibility; The antibacterial particles have good compatibility with the matrix resin, and the particles are substantially completely embedded by the matrix resin, and the interface between the two is continuous without phase separation. It can be seen that the surface treatment of the antibacterial particles not only improves the dispersibility 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 interface. The adhesion, which plays a large role in improving the mechanical properties of the antibacterial polypropylene.
2.2 Antibacterial particles affect the crystal structure of polypropylene. The yellow line (upper curve) represents antibacterial polypropylene; the lime line (lower curve) represents the DSC curve of polypropylene antibacterial polypropylene. It can be seen that 1% antibacterial powder is added, and the melting temperature of I>P ( Tm) has improved. Moreover, the melting exotherm of the antibacterial PP is narrow and narrow, and the exothermic peak area is increased, which indicates that the antibacterial PP has a more complete crystal structure and higher crystallinity.
This is attributed to heterogeneous nucleation-induced crystallization of inorganic antibacterial particles in the PP matrix. The surface modification improves the compatibility of the polar inorganic antibacterial particles with the non-polar PP, facilitates the contact of the inorganic antibacterial particles with the PP matrix, activates the nucleation sites on the surface of the antibacterial particles, increases the nucleation point of the induced crystallization, and increases the crystallinity. The crystal size is reduced and the structure is more complete.
2.3 Effect of Antibacterial Particles on Mechanical Properties of Polypropylene 2.3.1 Effect of Draft Ratio on Mechanical Properties of Polypropylene The antibacterial PP virgin fiber has low strength and high elongation. It does not have the requirements for use, and the mechanical properties of the fiber should be improved by post-draw. The mechanical properties of the antimicrobial PP primary fibers at different draw ratios are shown. The breaking strength of the blank PP fiber and the antibacterial PP fiber increased with the increase of the 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, because the antibacterial particle is an inorganic rigid particle, although the surface treatment improves its compatibility with the PP matrix, but It is impossible to achieve a fully compatible level. Therefore, under the stress of the phase interface where the compatibility between the two is slightly poor, the damage is firstly caused, which becomes the starting point of the overall performance failure of the material, so that the mechanical properties of the material rapidly decrease; In addition, some particles of larger particle size in the antibacterial particles are also responsible for the structural properties of the material. 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 PP molecular chain to move, and the draw ratio increases. Larger, the smaller the fiber fineness, the rapid decrease in plasticization and the large decrease in elongation at break.
It can be seen from the figure that when the draft ratio exceeds 7 times, the breaking strength of the antibacterial PP fiber exceeds 4 cN/dtex, and after 8 times of drawing, the breaking strength and the elongation at break of the two are not much different, therefore, By not reducing the other properties, the breaking strength of the antibacterial fiber can be increased by increasing the draft ratio, and the elongation at break can be lowered to meet the practical application requirements.
Since the antibacterial fiber is mainly used for the production of underwear and hosiery, the colluding strength of the fiber is also an important performance. As shown, the colloidal strength of the antibacterial fiber is increased with the increase of the draw ratio, and the elongation at break of the hook is gradually reduced. This is similar to changes in tensile strength at break and elongation. But both are generally higher than the blank PP fiber. Comparing the data, it is known that the antibacterial fiber has the best mechanical properties when the draft ratio is 8 times. Therefore, it is important to study the mechanical properties of antibacterial fibers at different draw ratios and to antibacterial PP fibers with excellent textile properties.
2.3.2 Effect of anti-seed masterbatch on the mechanical properties of polypropylene. Antibacterial particle content Breaking strength (cN/dtex) Elongation at break ratio: 4 From Table 1, it can be seen that with the increase in the amount of antibacterial powder, Under the condition of low draft ratio, there is no obvious change. When the draft ratio is increased, the breaking strength of the fiber decreases, and the elongation at break decreases under different draft ratios. This is because the antibacterial particles are added, which has a high effect. 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 degraded. Therefore, the size of the antibacterial particles must be strictly controlled and uniform. Degree and dispersion in the fiber, and while reducing the antibacterial properties, try to reduce the amount.
2.4 Anti-seedling performance of anti-miao polypropylene Table 2. Antibacterial properties of antibacterial C to Escherichia coli and Staphylococcus aureus Strain initial colony number (cfu/m) Survival colony number (cfu/m) sterilization rate after 24h The active value of Escherichia coli antibacterial polypropylene blank polypropylene control sample Staphylococcus aureus antibacterial polypropylene blank. The polypropylene control sample shows that the antibacterial cockroach has excellent antibacterial properties against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (E. coli), and its bactericidal rate has reached 99.9% or more. The antibacterial activity values ​​are far more than 2.0. It can be seen that the antibacterial polypropylene has strong bactericidal and bacteriostatic effects.
(Antibacterial fiber dosage 100mg/ml, l blank; 2 antibacterial fiber; 3 antibacterial fiber after washing) Antibacterial properties of antibacterial polypropylene after washing as shown. After 6h of boiling water treatment, a small part of the antibacterial particles on the surface of the fiber will be removed from the fiber surface, which will reduce the antibacterial property of the polypropylene fiber, but the inner deep particles will slowly migrate to the fiber surface under the driving force of the concentration difference, so that the antibacterial ability is obtained. Supplementation, so that the antibacterial properties of the fiber are not reduced to a large extent, the fiber still has good antibacterial properties, it is for this reason that the antibacterial fiber has long-lasting antibacterial properties.
3 Conclusion After surface treatment, the antibacterial particles dispersed well in polypropylene and had good compatibility with PP matrix.
By changing the draft ratio, an antibacterial PP fiber having excellent performance can be obtained, and its mechanical properties are comparable to those of ordinary polypropylene.
The 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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