What is polymer IV?
What is polymer IV?
Intrinsic Viscosity (IV) is a measure of the polymers molecular weight and therefore reflects the material’s melting point, crystallinity, and tensile strength.
What is the molecular weight of PLA?
16.000 g/mol
Nagahata et al. [36] reported the synthesis of PLA with a molecular weight of ≈16.000 g/mol by a single-step direct polycondensation of LA, which can be achieved by effectively using microwave irradiation.
Is lactide a polymer?
Poly(lactide) is a 35% crystalline polymer with a modulus of 4.8 GPa making it considerable more flexible than poly(glycolide). Due to hydrolysis of the ester backbone, poly(lactide) loses most of its strength after 6 months in vivo.
How is molecular weight of polymer determined by viscosity method?
In this method viscosity of liquid is measured by comparing the flow times of two liquids of equal volumes using same viscometer. The molecular weight of the polymer is measured by using viscometer and the molecular weight obtained by this technique is called viscosity average molecular weight.
Is PLA a polymer?
PLA polymers range from amorphous glassy polymer to semi-crystalline and highly crystalline polymer with a glass transition 60–65 °C, a melting temperature 130-180 °C, and a Young’s modulus 2.7–16 GPa. Heat-resistant PLA can withstand temperatures of 110 °C.
What is L lactide?
Lactide is the lactone cyclic ester derived by multiple esterification between two (usually) or more molecules from lactic acid (2-hydroxypropionic acid) or other hydroxy carboxylic acid. The dilactide derived from lactic acid (with the formula (OCHMeCO2)2) exists in three different stereoisomeric forms.
What is meso lactide?
Meso-lactide (MLA) was synthesized by thermal degradation of poly(l-lactide) [i.e., poly(l-lactic acid) (PLLA)] at relatively high temperatures of 250 and 300 °C for thermal degradation periods up to 750 and 360 min, respectively.
How is PLA made?
PLA is a polyester made through the fermentation under controlled conditions of a carbohydrate source like corn starch or sugarcane. The starch is then mixed with acid or enzymes and heated. This process “breaks” starch into dextrose (D-glucose), or corn sugar.
What is the molecular weight of polymer?
A polymer’s molecular weight is the sum of the atomic weights of individual atoms that comprise a molecule. It indicates the average length of the bulk resin’s polymer chains. All polymer molecules of a particular grade do not have exactly same molecular weight. There is a range or distribution of molecular weights.
What is a poly (lactide-co-glycolide) or PLG?
We produce poly (lactide- co -glycolide)s, also referred to as PLGs or PLGAs, by ring-opening polymerization from lactide and glycolide monomers. Their degradation properties and long history of use in human products make PLGAs desirable for drug delivery, medical device and combination products.
What is the IV data for 50 50 poly?
The IV data for the 50:50 poly (DL-lactide- co -glycolide) and 65:35 poly (DL-lactide- co -glycolide) were obtained in hexafluoroisopropanol (HFIP). The IV data for the four remaining polymer compositions were obtained in chloroform.
How is molecular size measured in GPC?
Gel Permeation Chromatography (GPC) is a chromatographic method for measuring molecular size. The molecular size can be expressed as molecular weight (MW) obtained from calibration with a standard polymer such as polystyrene.
What is the unit of IV in gel chromatography?
The units of IV are typically reported in deciliters per gram (dL/g). IV is simple and inexpensive to obtain and reproducible between different laboratories. Gel Permeation Chromatography (GPC) is a chromatographic method for measuring molecular size.
