Factors affecting degradable materials

There are many factors that affect the degradation performance of materials, including the following:
The influence of pH value on the degradation of polymer materials
Mader et al. believe that changes in pH have a significant impact on the hydrolysis rate of copolymer chains, but the degradation rate does not differ significantly in different parts of the organism. The degradation of copolymers can form an acidic microenvironment, which promotes the self catalysis of copolymers, leading to their degradation
The influence of temperature on the degradation of polymer materials
It is rare to see any relationship between material degradation and temperature in experiments, as in vitro experiments often simulate body temperature, and human body temperature does not change much. However, during in vitro experiments, sometimes for the sake of experimental needs, it is possible to increase the temperature appropriately to shorten the experimental period. However, during the accelerated degradation process, the temperature should not be too high or too low, as polymers may experience side reactions when the temperature is too high; When the temperature is too low, the goal of accelerating degradation cannot be achieved. So, to avoid the impact of temperature and air flow on biodegradable materials, biodegradable materials are stored in a low-temperature sealed environment
The influence of molecular weight on the degradation of polymer materials
Wu et al. believe that the hydrolysis rate of materials is significantly influenced by the molecular weight and distribution of copolymers. This is mainly because each ester bond can be hydrolyzed, and the hydrolysis of ester bonds on the molecular chain is irregular. As the polymer molecular chain is longer, it can undergo hydrolysis at more locations, resulting in faster and faster degradation.
The influence of material structure on the degradation of polymer materials
Anhydride and acid esters are easily hydrolyzed. Li et al. believe that the rapid decrease in mass and molecular weight of comb copolymers is due to the polarity of the skeleton, which facilitates the cleavage of ester bonds. So the degradation rate of comb like molecular copolymers is higher than that of linear molecules.
The influence of monomer composition ratio on the degradation of polymer materials
The degradation behavior of materials is related to their physical and chemical properties, and the polarity, molecular weight, and distribution of polymers all affect their degradation performance. After research, Wu et al. believed that the degradation of copolymers is closely related to their molecular weight, crystallinity, and other factors. The crystallinity of copolymers of ethylene glycol and propylene glycol is lower than that of their respective homopolymers.
Glycolic acid is more hydrophilic than lactic acid, therefore, PGLA copolymers containing more ethylene glycol have better hydrophilicity than those containing more propylene glycol, resulting in faster degradation rate. Hydrophilic polymers have a high water absorption capacity, and the internal molecules of the material can fully contact with water molecules, resulting in a fast degradation rate. On the contrary, hydrophobic polymer materials have less contact between internal molecules and water molecules, resulting in a slower degradation rate.
The effect of enzymatic hydrolysis on the degradation of polymer materials
There are many reactions in living organisms that can lead to the degradation of polymers, including oxidation in body fluids, chemical hydrolysis, and enzymatic reactions. Hollalld et al. believe that in the early glassy state, enzymes are difficult to participate in degradation, but enzymatic hydrolysis is the main factor affecting copolymers in the rubber gel state.
The influence of polymer hydrophilicity/hydrophobicity on the degradation of polymer materials
Hydrophilic polymers can absorb a large amount of water and accelerate the degradation rate; Hydrophobic polymers have low water absorption and slow degradation rate. Especially polymers containing hydroxyl and carboxyl groups are more prone to degradation.