Question : PLA - polylactic acid
it is a biodegradable polymer used as a substitute for petroleum based plactics.
Answer : There are several suppliers that will provide you with PLA of various sorts (different chemical end-groups, different average mol. wt, etc.), as well as related polymers like PLGA.
We get ours from Boehringer Ingelheim:
also produce them.
You'll need to ask them for quotes, but some might also give free samples. IIRC, we paid 1,177 for 5x50g of different PLGA types.
You may have to produce pellets of them yourself, if you require a pellet form, as we get the PLGA as a powder.
If you are making microparticles - read up on coacervation, and spray-drying as techniques for microparticle production.
Question : need to know what polymers are.maybe some examples and the main types of polymers.... in FOOD... maybe give some examples and main polymers...in FOOD...
Answer : A polymer is a very large organic molecule made up from many smaller molecules joined together. The small molecules are known as monomers and most polymers are made up of one or two different types of monomer.
The first commercially produced polymer is also the simplest and most common: polythene. Its systematic name is poly(ethene) meaning it is a polymer made from the monomer, ethene. Ethene is a small molecule containing two carbon atoms linked by a double bond and four hydrogen atoms, two bonded to each carbon.
When ethene is subjected to high temperature and pressure, or reacted in the presence of a catalyst, one of the bonds in the double bond is broken. Each of the carbon atoms then has a free electron which can form a covalent bond by pairing with another free electron. If other ethene molecules are present, the double bond in one of them can break, and the free electron on one of the carbons can combine with another on the original molecule..
Question : A company recieves two batches of the same polymers. When tested these were found to have the same chemistry and structure but considerably different mechanical properties. Suggest one possible reason.
Answer : Polymer is a term used to describe large molecules consisting of repeating structural units, or monomers, connected by covalent chemical bonds. The term is derived from the Greek words: polys meaning many, and meros meaning parts . A key feature that distinguishes polymers from other molecules is the repetition of many identical, similar, or complementary molecular subunits in these chains. These subunits, the monomers, are small molecules of low-to-moderate molecular mass, and are linked to each other during a chemical reaction called polymerization.
Similar monomers can have various chemical substituents. These differences between monomers can affect properties such as solubility, flexibility, and strength. In proteins, these differences give the polymer the ability to adopt a biologically-active conformation. (See self-assembly.) Identical monomers with nonreactive side groups result in a polymer chain that will tend to adopt a random coil conformation, as described by an idea..