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Polymer Synthesis CHEM 421 Reading (Odian Book): Chapter 1.

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Presentation on theme: "Polymer Synthesis CHEM 421 Reading (Odian Book): Chapter 1."— Presentation transcript:

1 Polymer Synthesis CHEM 421 Reading (Odian Book): Chapter 1

2 Polymer Synthesis CHEM 421 Polymer Parameters Chemical structure –Chemical composition and distribution –Sequence length and distribution Molecular weight and distribution Chain isomerism Morphology Topology Additives Cost

3 Polymer Synthesis CHEM 421 Chemical Composition

4 Polymer Synthesis CHEM 421 Chemical Composition Infinite chain model notation How best to characterize? Why does sequencing matter? Synthetic approaches? Compositional distribution? Branching? (refer to as topology…)

5 Polymer Synthesis CHEM 421 Polymer Parameters Chemical structure –Chemical composition and distribution –Sequence length and distribution Molecular weight and distribution Chain isomerism Morphology Topology Additives Cost

6 Polymer Synthesis CHEM 421 Molecular Weight Property “X” Molecular Weight “X” = tensile strength density Tg etc

7 Polymer Synthesis CHEM 421 Molecular Weight M n = Σ n i M i Σ niΣ ni M w = Σ w i M i Σ wiΣ wi

8 Polymer Synthesis CHEM 421 Molecular Weight M n = Σ n i M i Σ niΣ ni M w = Σ w i M i Σ wiΣ wi Populations –Memphis, TN700,000 –Montrose, CO 10,000 –Effingham, IL 12,000 –Freeman, SD 1,500 What is the Average Population? –723,500 ÷ 4 = 180,875 –Of these four cities, the average city population is 180,875 Let’s think about the people… What size city does the average person among these populations live in? –The average person does not live in a town of a population of 180,875… –Most of the people live in a town with a lot more than 180,000 people… –Need a weighted average

9 Polymer Synthesis CHEM 421 Molecular Weight M n = Σ n i M i Σ niΣ ni M w = Σ w i M i Σ wiΣ wi Populations –Memphis, TN700,000 –Montrose, CO 10,000 –Effingham, IL 12,000 –Freeman, SD 1,500 Weighted average –700,000 ÷ 723,500 = –Take fraction and multiply that by the population of Memphis x 700,000 = 677,263 –Do the same for the others »700,000 x 700,000 / 723,500 = 677,263 » 10,000 x 10,000 / 723,500 = 138 » 12,000 x 12,000 / 723,500 = 199 » 1,500 x 1,500 / 723,500 = 3 677,603 –The average person lives in a city of about 677,600 –More realistic than saying the average person lives in a city of 180,000!

10 Polymer Synthesis CHEM 421 Molecular Weight What is the significance of the spread? Polydispersity index (PDI) PDI of polypeptides and DNA How does magnitude of MW relate to synthesis? How do you control PDI? M n = Σ n i M i Σ niΣ ni M w = Σ w i M i Σ wiΣ wi

11 Polymer Synthesis CHEM 421 Molecular Weight Distribution

12 Polymer Synthesis CHEM 421 Gel Permeation Chromatography What is principle behind GPC? Direct or indirect method? Why so useful? Drawback? Detector Response Elution Volume (mL)

13 Polymer Synthesis CHEM 421 Time of Flight Mass Spectrometry (TOF-SIMS)

14 Polymer Synthesis CHEM 421 Time of Flight Mass Spectrometry (TOF-SIMS)

15 Polymer Synthesis CHEM 421 Time of Flight Mass Spectrometry (TOF-SIMS)

16 Polymer Synthesis CHEM 421 Polymer Parameters Chemical structure –Chemical composition and distribution –Sequence length and distribution Molecular weight and distribution Chain isomerism Topology Morphology Additives Cost

17 Polymer Synthesis CHEM 421 Chemical Composition Distribution (CCD) Interplay between CCD and MWD… How to measure? Ramifications? –Catalysis? –Phase separation? –Optical properties? –Degradation rates? –Toxicity? Sequence length distribution

18 Polymer Synthesis CHEM 421 Polymer Parameters Chemical structure –Chemical composition and distribution –Sequence length and distribution Molecular weight and distribution Chain isomerism Morphology Topology Additives Cost

19 Polymer Synthesis CHEM 421 Chain Isomerism Regio-isomers Stereo-isomers Geometric isomers Conformational isomers

20 Polymer Synthesis CHEM 421 Regio-isomers defect

21 Polymer Synthesis CHEM 421 Regio-isomers

22 Polymer Synthesis CHEM 421 Regio-isomers


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