Molecular weight and viscosity

Virtually crosslinked (VC) products, 201 Viscometry, of polyamides, 161-162 Viscosity, molecular weight and, 3 VK column reactor, 175 Volatile organic compounds (VOCs), 206, 207... 

Cross,M. M. Viscosity, molecular weight, and chain entanglement. Polymer (London) 11,238-244 (1970). 

Fox TG, Flory PJ (1948) Viscosity-molecular weight and viscosity-temperature relationships for polystyrene and polyisobutylene. J Am Chem Soc 70(7) 2384-2395 Freed KF, Edwards SF (1974) Polymer viscosity in concentrated solutions. J Chem Phys 61(9) 3626-3633... 

Today, there is more emphasis on quality of excipients. For example, some inherent quality variability may occur in the natural products magnesium stearate and sodium starch glycolate. What is the impact of the variability of these excipients on product quality attributes Also, excipient viscosity, molecular weight, and particle size relative to API particle size could be critical factors to some formulations. An optimal dissolution method can only be developed on the basis of knowledge of the dmg product. 

A different line of approach has been used by Flory and Brant for the evaluation of the characteristic ratio of four polypeptides on the basis of intrinsic viscosity, molecular weight and second virial coefficient data 53). 

M 22. Moore, L. D., JR. Relations among melt viscosity, soluBon viscosity, molecular weight and long-chain branching in polyethylene. J. Polymer Sci. 36, 155-172 (1959). 

Viscosity molecular weight and molecular weight distribution... 

Figure 4. Flory-Mandelkern correlation of intrinsic viscosity, molecular weight, and translational diffusion coefficient for a variety of polymer solvent systems, demonstrating the insensitivity of these data to the structure of the macromolecule ( X PS/tetrahydrofuran (37) (O), protein random coils in 6M guanidine hydrochloride-0,IM mercaptoethanol (26) (X), tobacco mosaic virus in aqueous solution (11) ( ), bovine serum albumen in aqueous solution (37).

According to the Mark-Houwink-Sakurada equation, the relationship between the viscosity, molecular weight, and organic polymer type can be formulated as... 

Gupta, P., C. Elkins, T.E. Long, and G.L. Wilkes. Electrospinning of linear homopolymers of poly (methyl methacrylate) exploring relationships between fiber formation, viscosity, molecular weight and concentration in a good solvent. Polymer 46(13) (2005) 4799 810. 

Process oils in a rubber formulation serve primarily as a processing aid. Oils fall into one of three primary categories paraffinic, naphthenic, and aromatic. The proper selection of oils for inclusion in a formulation is important. If the oil is incompatible with the polymer, it will migrate out of the compound with consequent loss in required physical properties, loss in rubber component surface properties, and deterioration in component-to-component adhesion, as in a tire. The compatibility of an oil with a polymer system is a function of the properties of the oil such as viscosity, molecular weight, and molecular composition. Table XXVIII defines the physical properties of three typical classes of oils. 

TVE monomer can be solution advanced at 150°C in typical solvents to a precisely controlled viscosity, molecular weight, and polydispersity." The prenetwork branched oligomer solutions can be spin-coated and cured giving optically clear films which exhibit exceptional planarization and gap fill in microelectronics and flat panel display applications. Structures can also be molded from the melt and mechanical properties such as tensile and flexural moduli for the TVE thermoset (both near 2300 MPa) have been measured. ... 

The most commonly applied methods in the study of oxidative degradation are determination of changes in intrinsic viscosity, molecular weight and molecular weight distribution, number of scissions, oxygen uptake, spectrometric methods, thermal methods, chemiluminescence, determination of electrical and mechanical properties and of gel content, etc., all helping to establish the induction period. 

Fox TG, Hory PJ. Viscosity-molecular weight and viscosity-temperature relationships for polystyrene and polyisobutylene. J Am ChemSoc 1948 70 2384-95. 

Liquid polysulfides can also be prepared directly with thiol end groups by reacting a mixture of aliphatic di- and polyhalides with a mixture of sodium disulfide and sodium hydrogen sulfide [77]. Reaction polymeric disulfides with polymercaptans also leads to the formation of liquid polysulfides [37]. LP polymers with M in the range of 600 to 8000 are generally f eferred. The uncured LP polymers are soluble in toluene, benzene and chlorinated hydrocarbons such as ethylene chloride [17, 78]. LP polym like LP-31, LP-2, LP-32, LP-12, LP-3, LP-33, LP-5, LP-8, based on range of viscosities, molecular weights and functionalities, are available [17]. 

Kwaambwa, H.M. et al., 2007. Viscosity, molecular weight and concentration relationships at 298K of low molecular weight cis-polyisoprene in a good solvent. Colloids and Surfaces A Physicochemical and Engineering Aspects, 294(1), pp. 14—19. 

---