The large surface area and ability to retain moisture of textile structures enable microorganisms' growth, which causes a range of undesirable effects, not only on the textile itself, but also on the user. Due to the public health awareness of the pathogenic effects on personal hygiene and associated health risks, over the last few years, intensive research has been promoted in order to minimize microbes' growth on textiles. Therefore, to impart an antimicrobial ability to textiles, different approaches have been studied, being mainly divided into the inclusion of antimicrobial agents in the textile polymeric fibers or their grafting onto the polymer surface. Regarding the antimicrobial agents, different types have been used, such as quaternary ammonium compounds, triclosan, metal salts, polybiguanides or even natural polymers. Any antimicrobial treatment performed on a textile, besides being efficient against microorganisms, must be non-toxic to the consumer and to the environment. This review mainly intends to provide an overview of antimicrobial agents and treatments that can be performed to produce antimicrobial textiles, using chemical or physical approaches, which are under development or already commercially available in the form of isolated agents or textile fibers or fabrics.

https://www.mdpi.com/1996-1944/9/6/498/pdf

Antimicrobial Approaches for Textiles: From Research to Market

Polylactic acid (PLA)-based polymers are ubiquitous in the biomedical field thanks to their combination of attractive peculiarities: biocompatibility (degradation products do not elicit critical responses and are easily metabolized by the body), hydrolytic degradation in situ, tailorable properties, and well-established processing technologies. This led to the development of several applications, such as bone fixation screws, bioresorbable suture threads, and stent coating, just to name a few. Nanomedicine could not be unconcerned by PLA-based materials as well, where their use for the synthesis of nanocarriers for the targeted delivery of hydrophobic drugs emerged as a new promising application. The purpose of the here presented review is two-fold: on one side, it aims at providing a broad overview of PLA-based materials and their properties, which allow them gaining a leading role in the biomedical field; on the other side, it offers a specific focus on their recent use in nanomedicine, highlighting opportunities and perspectives.

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A Perspective on Polylactic Acid-Based Polymers Use for Nanoparticles Synthesis and Applications.

Bio-plastics have gained tremendous attention, due to the increasing environmental pressure on global warming and plastic pollution. Among them, poly (lactic acid) (PLA) is both bio-based and bio-degradable, which has been widely used in many disposable packaging applications. The global market for PLA demand doubles every 3–4 years, as estimated by Jem's law. Compared to traditional petroleum-based plastics, PLA is more expensive and usually has less mechanical and physical properties. The recent compounding efforts and the commercialization of D(−) lactic acid and its polymer PDLA have the potential to improve the mechanical and thermal characteristics of PLA (e.g. by forming stereocomplex PLA) for applications in high-end markets. However, the usage of PLA in some other applications is still limited. With a structure similar to PLA, poly (glycolic acid) (PGA) has promising characteristics such as good biodegradability and barrier properties, which is potentially a beneficial supplement to PLA. The modification of PLA with PGA can be achieved via co-polymerization, physical blending and multilayer lamination. PGA and its combination with PLA have been widely studied in bio-medical applications, but not been well developed at large scales due to its relatively high production cost. In this case, the development of novel production technology and the advent of government regulations are the key drivers for the global transition towards bioplastics. Recently, multiple governmental regulations have been released that restrict the use of traditional plastics and facilitate bio-degradable plastic applications. PGA can be derived from industrial waste gases using an innovative production technology, which reduces carbon emissions and its production cost. By developing the production and compounding technology, PGA can be combined with PLA to play an essential role for a sustainable and environmental friendly plastic industry, especially for single-used products requiring fast degradation at room temperature or in the nature environment.

The development and challenges of poly (lactic acid) and poly (glycolic acid)

A review on degradation mechanisms of polylactic acid: Hydrolytic, photodegradative, microbial, and enzymatic degradation

Accelerated degradation of HAP/PLLA bone scaffold by PGA blending facilitates bioactivity and osteoconductivity.

Polylactic acid blends: The future of green, light and tough

The synthesis of high molecular weight poly (lactic-co-glycolic) acid (PLGA) copolymers via direct condensation copolymerization is itself a challenging task. Moreover, some of the characteristic properties of polylactide (PLA)-based biomaterials, such as brittleness, hydrophobicity, and longer degradation time, are not suitable for certain biomedical applications. However, such properties can be altered by the copolymerization of PLA with other biodegradable monomers, such as glycolic acid. A series of high molecular weight PLGAs were synthesized through the direct condensation copolymerization of lactic and glycolic acids, starting from 0 to 50 mol% of glycolic acid, and the wettability of its films was monitored as a function of the feed molar ratio. Copolymerization was performed in the presence of a bi-catalytic system using stannous chloride dihydrate and methanesulfonic acid (MSA). The viscosity average molecular weight of the resulting PLGA was in the range of 80k to 135k g/mol. The PLGA films were prepared using the solvent casting technique, and were treated with oxygen plasma for 2 min. The water contact angle of the PLGA films was determined before and after the oxygen plasma treatments, and it was observed that the wettability increased with an increase in the glycolic acid contents, however, the manifolds increased after 2 min of oxygen plasma treatments.

https://www.mdpi.com/2073-4360/10/10/1132/pdf

Effect of Chemical Composition Variant and Oxygen Plasma Treatments on the Wettability of PLGA Thin Films, Synthesized by Direct Copolycondensation.

Poly(butylene Succinate) (PBS): materials, processing, and industrial applications

Polyglycolic acid (PGA) was successfully synthesized via solution and melt/solid polycondensations. PGA was synthesized by solution polymerization under vacuum by using diphenylsulfone as solvent and methanesulfonic acid as catalyst and the inherent viscosity of resultant PGA was 0.2 dl/g. The intrinsic viscosity was obtained up to 0.35 dl/g of the PGA synthesized by melt/solid polycondensation. Whereas, PGA synthesized by longer hours of SSP was insoluble in most of the known solvents, which might have higher molecular weight as well as crystallinity. Crystallographic structure of PGA was confirmed by XRD and the resulting PGA polymer was similar in thermal degradation to that of commercially available polyglycolide (Kuredux), synthesized by ring opening polymerization. Both PGAs were characterized for thermal decomposition kinetic studies using thermaogravimetric analysis (TGA), to investigate the effect of end-group and molecular weight on thermal degradation behavior. TGA was performed at 6 different heating rates from 5 to 50 °C/min and data was analyzed by three different approaches to obtain activation energy. Activation energy from Kissinger’s approach was 112 kJ/mol for lab synthesized PGA and 119 kJ/mol for Kuredux, whereas from Flynn and Wall’s method, it was observed as 115 kJ/mol and 121 kJ/mol for solution-polymerized PGA and Kuredux respectively and activation energies calculated from dynamic experiment method was also comparable of both PGAs. From dynamic experiment method linearity curve starts as low as 1 % decomposition and continues as high as 97 % with decomposition temperature ranges 219 to 380 °C for PGA and 230 to 406 °C for Kuredux. Consequently, Kissinger’s method, Flynn and Walls method and the dynamic experiment method reveal that the thermal decomposition behavior of polyglycolic acids and polyglycolide is similar, regardless of end groups and synthetic routes which is supposed to be random chain cession.

Synthesis of poly(glycolic acids) via solution polycondensation and investigation of their thermal degradation behaviors

*Faculty of Pharmacy, Bahauddin Zakariya University, 60800 Multan, Pakistan E-mail: engr.furqan@bzu.edu.pk Abstract The aim of the present work was to assess an eco friendly natural antimicrobial textile finish extracted from Aloe gel and Neem plants. Extracted Aloe gel and active substance of Neem were mixed in a mordant to form a finish. Bleached cotton samples were treated with 5, 7, and 10% concentrations of Aloe gel and Neem separately. The same samples were then treated with a hybrid combination of Aloe gel and Neem (HCAN) extracts having 5, 7 and 10% concentrations. These finished samples were subjected to an antibacterial activity test against E. coli and S. aureus, an antifungal activity test against Aspergillus Niger, and a test of their durability of antibacterial finish fastness to washing by standard test methods. It was found that the hybrid combination of Aloe gel and Neem (HCAN) was an effective antibacterial and antifungal agent as compared to Aloe gel and Neem separately. It also showed good durability to washing.

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Muhammad Ayyoob

Papers

Polylactic acid blends: The future of green, light and tough

Effect of Chemical Composition Variant and Oxygen Plasma Treatments on the Wettability of PLGA Thin Films, Synthesized by Direct Copolycondensation.

Poly(butylene Succinate) (PBS): materials, processing, and industrial applications

Synthesis of poly(glycolic acids) via solution polycondensation and investigation of their thermal degradation behaviors

Assessment of Eco-Friendly Natural Antimicrobial Textile Finish Extracted from Aloe Vera and Neem Plants