Which polymer shows pH dependent swelling?
Which polymer shows pH dependent swelling?
The chemical structure of xanthan is shown in Figure 8. Figure 8. Chemical structure of Xanthan. Xanthan, being an ionic polymer, containing a carboxylic group on one of the side chain of glucuronic acid is pH sensitive and shows much swelling in basic environment due to complete ionization of the carboxylic group.
Does pH affect swelling ratio?
Effect of pH on swelling Slight change in swelling ratio of the biomineralized hydrogels has been noticed when placed in various pH of the aqueous solution. In pH = 7, water molecules undergo H2 bonding so generates more space for the molecules to penetrate inside, thus swells more.
What is pH dependent polymer?
Polymers with pH-sensitive chemical linkages, such as hydrazone, acetal, ortho ester and vinyl ester, pH-sensitive cell-penetrating peptides and cationic polymers undergoing pH-dependent protonation have been studied to utilize the pH gradient along the endocytic pathway for intracellular drug delivery.
How do pH sensitive polymers work?
pH sensitive or pH responsive polymers are materials which will respond to the changes in the pH of the surrounding medium by varying their dimensions. Materials may swell, collapse, or change depending on the pH of their environment.
What is cationic polymer used for?
Cationic polymers are used to prepare bioactive coatings that kill bacteria upon contact without the release of any chemicals from the cationic molecules themselves.
What is the normal pH of gastric fluid?
The normal volume of the stomach fluid is 20 to 100 mL and the pH is acidic (1.5 to 3.5). These numbers are converted to actual acid production in units of milliequivalents per hour (mEq/hr) in some cases.
Is the swelling of a part of the body?
Edema is swelling that is caused by fluid trapped in your body’s tissues. Edema happens most often in the feet, ankles, and legs, but can affect other parts of the body, such as the face, hands, and abdomen. It can also involve the entire body.
How do you calculate the ratio of swelling?
Tea bag test method and weigh the bag and then calculate the percentage of swelling through the following formula: (w2-w1)/(w1) % w1= weight of the polymer (Before swelling) w2= weight of the polymer (After swelling)
Is pH dependent on concentration?
In general, the pH of an acid solution will be lower as the solution is more concentrated. For bases, the pH will be higher with more highly concentrated solutions.
Which one is a natural polymer?
Examples of naturally occurring polymers are silk, wool, DNA, cellulose and proteins. In our previous section on network polymers, we mentioned vulcanized rubber and pectin. Vulcanized rubber is a synthetic (man-made) polymer, while pectin is an example of a natural polymer.
Which polymer is used in pigment?
Amongst the inorganic pigments titanium dioxide is the most widely used pigment in the plastics industry. Pigment families are mainly categorized into: Organic pigments.