Quantitative Analysis of Copolymers by GPC/FT-IR

1996 ◽  
Vol 50 (3) ◽  
pp. 349-356 ◽  
Author(s):  
Michael X. Liu ◽  
James L. Dwyer
Keyword(s):  
Molecular Weight ◽  
Infrared Spectroscopy ◽  
Quantitative Analysis ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Spectral Peak ◽  
Combined Method ◽  
Calibration Standards ◽  
Ft Ir ◽  
Styrene Butadiene

A combined method of chromatography and infrared spectroscopy is employed to map the distribution of monomers in copolymer samples. The method relies on the measurement of spectral peak ratios of the sample, using polymer samples of known composition as calibration standards. The inherent variation of the method was established by measuring a homopolymer of invariant composition. The samples examined were styrene/butadiene copolymers, synthesized by two different polymerization protocols. The technique provided sensitive measurement of comonomer composition across the molecular weight distribution of the samples and is generally applicable to copolymers that can be fractionated by chromatographic methods.

Novel Polyaspartic Ester Polyureas Based on Flexible Polyaspartic Ester

2011 ◽  
Vol 197-198 ◽  
pp. 1294-1298
Author(s):  
Ping Lu ◽  
Wei Bo Huang ◽  
Xue Qiang Ma ◽  
Xu Dong Liu
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Hydrogen Bonding ◽  
Molecular Weight Distribution ◽  
Michael Addition ◽  
Weight Distribution ◽  
Addition Reaction ◽  
Chain Extender ◽  
Michael Addition Reaction ◽  
Ft Ir

New polyaspartic ester (PAE) chain extender named PAE-f was prepared via two steps of Michael addition reactions:(1) Michael addition reaction between 4,4’-methylenebis(2-methyl cyclohexyl amine) (Laromin C260) and excessive dialkyl maleates（DEF）; (2) The Michael addition reaction of the residual dialkyl maleates of step (1) with polyester polyamine Jeffamine D230. The two-steps method proposed could reduce the reaction time in comparison with the current one step Michael addition reaction method, thus satisfying the industrialized production. New PAE based polyureas were synthesized by reacting the PAE-f chain extender with aliphatic polyisocyanates 4,4’-diisocyanato dicyclohexylmethane (H12MDI) / polyester polyamine Jeffamine D2000 prepolymer at room temperature. FT-IR and GPC were employed to characterize the new PAE prepared, and the morphology, molecular weight distribution and mechanical properties of the prepared PAE based polyureas were investigated by means of FT-IR and GPC. The FT-IR results indicated that the hydrogen bonding degree of amidogen groups in hard segments of the prepared polyureas were high, the length of hydrogen bonding were 0.305nm～0.306nm. The GPC experimental results show that the weight average molecular weight of the PAE-f based polyureas were 4.95×104～6.05×104,Mw/Mn were 1.65～1.97, the molecular weight distribution were relatively narrow. The mechanical properties demonstrated that the tensile strength were 14.7～22.5MPa, Elongation at break were 306～511%, Yang’s modulus were 67～127MPa, Shore A hardness were 64～83. The mechanical properties confirmed that the polyureas based on PAE-f were kinds of elastomeric materials with satisfied flexibility, strength, module and hardness.

EFFECT OF REVERSIBLE ADDITION-FRAGMENTATION CHAIN TRANSFER EMULSION STYRENE–BUTADIENE RUBBER ON THE PROPERTIES OF SILICA COMPOUNDS

2020 ◽  
pp. 000-000 ◽  
Author(s):  
Hyunsung Mun ◽  
Kiwon Hwang ◽  
Gwanghoon Kwag ◽  
JaeKon Suh ◽  
Duseong Ahn ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Raft Polymerization ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Narrow Molecular Weight Distribution ◽  
Reversible Addition ◽  
Raft Agent ◽  
Styrene Butadiene

ABSTRACT In recent years, solution styrene–butadiene rubber (SSBR), which has a narrow molecular weight distribution, controllable microstructure, and chain end functionality, is mainly used as base rubber for passenger car tire tread compounds. However, SSBR has a lower molecular weight than that of emulsion SBR (ESBR) because it is difficult to increase the molecular weight of SSBR. In contrast, ESBR can easily increase the molecular weight; however, it has a broad molecular weight distribution. The reversible addition-fragmentation chain transfer (RAFT) polymerization technique is applicable to the emulsion polymerization. Polymers with narrow molecular weight distributions can be obtained by the RAFT polymerization because the RAFT agent prevents the coupling reaction of the growing chain radicals. In this case, ESBR having a narrow molecular weight distribution, which is an advantage of SSBR, and a high molecular weight, which is an advantage of ESBR, can be synthesized. Therefore, we synthesized RAFT ESBR and fabricated its compounds with silica filler. We confirmed that the physical properties of the RAFT ESBR silica compound are different from those of the ESBR silica compound. In addition to the narrow molecular weight distribution of the RAFT ESBR, the trithiocarbonyl group of the RAFT agent in the RAFT ESBR chain molecules affects the physical properties.

Synthesis of Liquid Polyisoprene with High cis-1,4 Unit Content and Narrow Molecular Weight Distribution Using Neodymium Phosphate Catalyst

2019 ◽  
Vol 72 (6) ◽  
pp. 467 ◽  
Author(s):  
Jie Liu ◽  
Xin Min ◽  
Xiuzhong Zhu ◽  
Zichao Wang ◽  
Tong Wang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Catalyst System ◽  
Size Exclusion ◽  
Narrow Molecular Weight Distribution ◽  
13C Nmr Analysis ◽  
Exclusion Chromatography ◽  
Ft Ir ◽  
Ternary Catalyst

The polymerization of isoprene (Ip) initiated by a ternary catalytic system consisting of liquid Nd(P204)3 (Nd), Al(i-Bu)2H (Al), and CHCl3 (Cl) in cyclohexane was examined. The effects of order of addition and amount of Ip, Al, and Cl in the catalyst on the polymerization were evaluated. The molecular weight (Mn), molecular weight distribution (Mw/Mn), and microstructure of the polymer were characterized using size exclusion chromatography and multiangle light scattering, FT-IR, 1H NMR and 13C NMR analysis. The results indicate that the order of addition, i.e. Nd+Ip+Al+Cl and ratios of [Ip]/[Nd]=30, [Al]/[Nd]=20, and [Cl]/[Nd]=3 were essential for the optimized ternary catalyst system Nd(P204)3/Al(i-Bu)2H/CHCl3. The resulting liquid polyisoprene (LIR) has a high cis-1,4 unit content (>98%) and a narrow molecular weight distribution (Mw/Mn<1.2). The molecular weight of the polymer was precisely controlled.

scholarly journals Effect of Aging on the Rheological and Molecular Weight Distribution of Asphalt Binder Treated with Polyphosphoric Acid

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Tao Ma ◽  
Kai Yang ◽  
Rui Li ◽  
Jiujian Shen
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Polyphosphoric Acid ◽  
Asphalt Binder ◽  
Chemical Properties ◽  
Gel Permeation Chromatography ◽  
Weight Analysis ◽  
Styrene Butadiene

Asphalt binder behaves as a viscoelastic material and its inherit performance is dominated by rheological and chemical properties. Aging of asphalt binder is a prominent distress for long-term in-service asphalt pavement. In this work, the effect of aging on base asphalt modified by polyphosphoric acid (PPA) has been investigated. For the objective, virgin asphalt binder was modified by various dosages of PPA, styrene-butadiene-styrene (SBS), and PPA/SBS compound modification. The short- and long-term aging processes were simulated by Rolling Thin-Film Oven Test (RTFOT) and Pressure Aging Vessel (PAV) procedure. Rheological property of five aged modified binders was evaluated by the Dynamic Shear Rheometer (DSR). Meanwhile, gel permeation chromatography (GPC) was conducted to measure the molecular weight distribution and dispersion coefficient during the aging process. The high-temperature stiffness of PPA polymer binders is slightly higher than that of SBS and PPA/SBS compound modified asphalts. The aging ratio and molecular weight analysis verify the lower thermal-oxidative susceptibility of PPA/SBS compound modified asphalts. This study offers an understanding for the promotion and application of PPA modifier.

Polyether polyols as GPC calibration standards for determination of molecular weight distribution of polyether polyols

2015 ◽  
Vol 132 (43) ◽  
pp. n/a-n/a ◽  
Author(s):  
Mohd Azmil Mohd Noor ◽  
Vahid Sendijarevic ◽  
Hazimah Abu Hassan ◽  
Ibrahim Sendijarevic ◽  
Tuan Noor Maznee Tuan Ismail ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Calibration Standards
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