In the case of MCQ/S, photoreduction forms macroradicals that recombine causing an increase in the molecular weight. a) Weight average molecular weight Chain growth involves initiation using an initiator and propagation of the polymer as a chain with a propagating chain end. When the number of monomers is very large, the compound is sometimes called a high polymer. Contents • Introduction • Determination of molecular weight • Polymer solutions • Viscometry • References 3. Introduction Synthetic polymers are polydisperse to varying degrees in a variety of ways. Neoprene . What are Polymers? Free PDF Download of CBSE Chemistry Multiple Choice Questions for Class 12 with Answers Chapter 15 Polymers. Because polymeric materials do not consist of strictly identical molecules, but instead are a mixture of many species having different values of \(DP\), the … Polymers and Molecular Weight GPC On Tour, Barcelona, 28th February 2012 1 . Which of the following belongs to the class of natural polymers?Options: oligomer: a low molecular weight polymer in which the number of repeating units is approximately between two and ten. Viscosity is defined as the measure of the opposing force of material to flow. Polymer Molecular Weight Distributions 11 Samples of synthetic polymers always contain polymer chains with a range of chain lengths One way to describe the length of the polymer chains is in terms of an average molecular weight, i.e the average of all the chain lengths in the sample HOWEVER…. The molecular weight is related to the glass transition temperature by the Fox–Flory Equation: T g =T g, ∞ ̶ (K/M n) (Fox-Flory Equation) where T g, ∞ is the glass transition temperature at the molecular weight of infinity, and K is … The polydispersity index of the polymer is a) Symmetry Professionals, Teachers, Students and Kids Trivia Quizzes to test your knowledge on the subject. And MALS detectors only require annual calibration. What physical property of a material refers to the amount of weight gain (%) experienced in a polymer after immersion in water for a specified length of time under a controlled environment? You have not finished your quiz. A number average molecular weight is obtained by methods that solely depend on the colligative properties of polymer solutions. The properties of the polymers depend on the distribution of molecular weights. 3. The size of the polymer is best discussed in terms of molecular weight. growing polymer molecule; (2) crosslink the polymer; (3) network the polymer; (4) form a thermosetting polymer ___ 19. References & Notes. A sample of a high polymer consist of 10% by weight of a macromolecule of molecular weight 10000 and 90% by weight of a macromolecule with molecular weight 100000, then its weight average molecular mass will be (a) 52000 (b) 85000 (c) 91000 (d) 89000. The molecular weight of polymer that is determined by viscometry is MV i.e. If loading fails, click here to try again, The polymer used in orthopedic devices and in controlled drug release is, The number average molecular mass and mass average molecular mass of a polymer are respectively 30,000 and 40,000. copolymer or higher mer polymers with various degrees of structural randomness further complicate a complete description of the molecular ensemble. Remove Filters; Clear Question Attempted × Botany. It can be expressed in different units such as poise and pascal second (Pa s = N s m-2). (d) Interaction with molecular chaperons. Correct Answer. The molar mass distribution of a … $\overline {M_w}$ is the weight average molecular weight. a) Monodisperse b) Polydispersity c) Cellulose chain d) Synthetic polymer High … View Answer, 5. p-Block Elements MCQs | Question – Paper 1. The unit of molecular weight of polymer is either kg/mol or g/mol. Your email address will not be published. The polydispersity index of polymer will be . Buoyant unit weight equals the saturated density (A) Multiplied by unit weight of water (B) Divided by unit weight of water (C) Plus unit weight of water (D) Minus unit weight of water. This makes determining a … Any items you have not completed will be marked incorrect. polyester: a polymer with a COOR repeating unit. AR, MCQ; Q. A __________ depicted as Mn, Let Ni equal the number of the molecules or moles or other calculated of number of molecules with mass M, or a calculated of mass such as D.P. 73. Block copolymers and polymer mixtures also offer significant challenges to evaluate their molecular weight distribution. Which compound form linear polymer due to H-bond? Determination of Molecular Weight of Polymers (Contd.) Very fast … Condensation polymerization involves the splitting out of a small molecule , usually water and (1) the presence of a carbon-carbon double bond; (2) the presence of a carbon-carbon The change of moisture content of soils, changes the (A) Value of the angle of repose (B) Amount of compaction required (C) Cohesive strength of soil (D) All the above. Theory: Viscosity is an internal property of a fluid that offers resistance to flow. (a) In aromatic solvents, the polymer molecular weight decreases with increasing basicity of the solvent. Answer: Option D. 16. 11) Zinc oxide and titanium oxide used in which GRDDS approach? Polymer degradation is a change in the properties—tensile strength, color, shape, or molecular weight—of a polymer or polymer-based product under the influence of one or more environmental factors, such as heat, light, and the presence of certain chemicals, oxygen, and enzymes. Our testing, insight and advice can assist you in your decision making process and help to ensure the integrity of the product. Molecular Weight : The glass transition temperature is also affected by the molecular weight of the polymer (Fig. High-molecular-weight polymers with weight-average molecular weight M w ∼ 10 5 were successfully obtained when excess 2,2′-dimethoxybiphenyl was used in the presence of several equivalents of AlCl 3 catalysts (entry 13, Table 1). A1.8). Number distribution and number average molecular weight (Mn)! The molecular weight of a particular polymer molecule is a product of the degree of polymerization and the molecular weight of the repeating unit. d) Polydispersity The polymer molecular weight is affected by several variables, such as (a) the type of solvent, (b) the monomer and cobalt concentration, (c) the concentration of the aluminum alkyl, (d) the polymerization temperature and (e) the monomer conversion. a) Natural b) Synthetic c) Semisynthetic d) Artificial 16 Ʃ Ʃ Formula is used for calculating _____ molecular weight. c) Weight average anion weight PDF unavailable: 32: Determination of Molecular Weight of Polymers (Contd.) The molecular weight of a polymer is determined by the chemical structure of the monomer units, the lengths of the chains and the extent to which the chains are interconnected to form branched molecules. Polymers: Molecular Weight and its Distribution 1. Knowing the Mark–Houwink parameters and the molecular weight of one of the polymers allows one to find the molecular weight of the other polymer using a GPC. To practice all areas of Pulp and Paper, here is complete set of 1000+ Multiple Choice Questions and Answers. b) Polydispersity View Answer, a) Number average molecular weight 15 Silk is an example of _____ polymer. These chains are compounded from multiple small molecules that can alter the mechanical behavior of the polymer and skew its molecular weight. polymer: a high molecular weight macromolecule made up … The mass average molecular mass & number average molecular mass of a polymer are respectively 40,000 and 30,000. In linear polymers the individual polymer chains rarely have exactly the same degree of polymerization and molar mass, and there is always a distribution around an average value.The molar mass distribution (or molecular weight distribution) describes the relationship between the number of moles of each polymer species (N i) and the molar mass (M i) of that species. d) Synthetic polymer B. Please visit using a browser with javascript enabled. polymerization is: Thermosetting polymer, Bakelite is formed by the reaction of High molecular weight is achieved early on and polymer is Introduction • In simple compounds there is some definiteness about the molecular weight, hence we can say the … b) Weight average A is some constant, and M is the molecular weight. The polymer sample contains chains of varying lengths, therefore, its molecular mass is always expressed as an average. Dependence of mechanical strength on polymer molecular weight. The chains in a sample may differ in, for example, molecular weight, degree of long or short-chain branching, stereostructure or composition (either grossly, as with copolymers, or slightly, as with end group or foreign moieties incorporated in the chain during … The advantage to determine molecular weight by … It is a way of determining the molecular mass of a polymer. A. Dacron B. Neoprene C. Melamine D. Glyptal 2. Stock Preparation & Additives for Papermaking, Calculations of Wood, Paper & Other Materials, here is complete set of 1000+ Multiple Choice Questions and Answers, Prev - Pulp & Paper Questions and Answers – Condensation Polymers, Next - Pulp & Paper Questions and Answers – Nomenclature, Electrical Machines Questions and Answers – Transformer Phasor Diagram, Electrical Machines Questions and Answers – Equivalent Circuit of Transformer, Chemical Process Calculation Questions and Answers, Engineering Chemistry I Questions and Answers, Chemical Engineering Questions and Answers, Polymer Engineering Questions and Answers, Pulp & Paper Questions and Answers – Wood Chips Preparation and Handling at the Pulp Mill, Pulp & Paper Questions and Answers – Wood Chip Measurement, Pulp & Paper Questions and Answers – Basic Optical Tests of Paper, Pulp & Paper Questions and Answers – Paper Machine, Pulp & Paper Questions and Answers – Basic Paper Properties, Pulp & Paper Questions and Answers – Internal Sizing, Pulp & Paper Questions and Answers – Sulphite Liquor Analysis, Pulp & Paper Questions and Answers – Wood Moisture Content and Density, Pulp & Paper Questions and Answers – Specific Types of Paper, Pulp & Paper Questions and Answers – General Grades of Paper, Polymer Engineering Questions and Answers – Distribution of Molecular Weight in Linear Polycondensation, Pulp & Paper Questions and Answers – Mechanical Properties of Paper. b) False Polymers are not restricted to monomers of the same chemical composition or molecular weight and structure. 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