Unanswered Questions
208 questions with no upvoted or accepted answers
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How does (E)CA glue ("super glue", "crazy glue", etc.) cure?
I use CA glue† very frequently in my shop, but I'm not entirely sure how it works. I've noticed three main modes of curing, I've emphasized the key observations:
When dispensed, it will remain fluid ...
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7
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98
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Do "random" "2D" polymers constrained to a box actually form "space filling" curves?
Background: The self avoiding walk model is (allegedly) a reasonable model for polymers, at least with respect to certain "universal" (i.e. lattice independent) constants -- see section 1.1. in this ...
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Why is the rubber tip of my capacitive stylus no longer conductive?
In 2014, so eight years ago, I bought five styluses from China. Cheap stuff obviously. They worked fine while I used them, but soon after they were just left in a drawer. Last night I realized that ...
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6
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614
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Thermophysical properties of liquid Galden LS 230 between 25 °C and 230 °C
I'm looking for thermophysical properties of Galden LS 230, a liquid polymer (PFPE) produced by Solvay (https://www.solvay.com/en/markets-and-products/featured-products/Galden.html) at temperatures ...
CommunityBot
- 1
6
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How to dissolve a strong resin in difficult situation?
The resin is made up from two components:
Component A: silicic acid, sodium salt (less than 10% sodium silicate)
Component B: Diphenylmethane-4,4'-Diisocyanate, isomers and homologs (MDI,Polymer-MDI)...
5
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65
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Dependence of elasticity on temperature and degree of vulcanization of typical commercial rubber band
I am doing a school experiment that tries to find how the elasticity of rubber band depends on temperature.
From all the research I have done, theory suggests stress to increase linearly with ...
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5
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81
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Oxygen tolerant RAFT polymerization using AIBN?
I want to do some RAFT polymerizations but don't have a nitrogen line at the moment. It seems that people have recently implemented oxygen scavenging strategies to enable open-air RAFT polymerization. ...
- 30.4k
5
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87
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What determines 3D printing material compatibility?
3D printing, specifically the type common for consumers FDM or FFF, involves laying down thin (typically 0.1 to 0.2mm) layers of molten plastic. Modern consumer printers can use various filaments: PLA,...
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183
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Why do aldehydes polymerize faster in the cold?
In amateur perfumery, raw chemicals are usually stored in sealed bottles in refrigerators/freezers to reduce decomposition rates. However, aldehydes are tricky to store for long periods of time ...
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Side chain formation in polymerisation of ethylene
I am having difficulty understanding (or at least need confirmation of my understanding) of this diagram regarding the formation of sidechains of polyethylene. If someone could explain it, that would ...
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178
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Regioselectivity in Ziegler–Natta polymerisation of α-olefins
Why does the Ziegler–Natta polymerization display the regioselectivity shown in the image? Internal nucleophiles (coordinated to the metal) should attack the alkene on the less substituted end, like ...
- 71.6k
5
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115
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UV curable adhesive
I'm looking for a UV curable adhesive that can be removed without peeling or burning. Ideal removal would be some kind of solvent over a relatively short period of time. I also need it to have a ...
4
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111
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How to estimate the mobility constant and the surface energy parameter in the Cahn-Hilliard equation?
As a mathematician, I want to simulate phase separations with the Cahn-Hilliard equation
$$
\frac{\partial c}{\partial t} = M \Delta \bigg(\frac{\partial \mu}{\partial c} - \kappa \Delta c \bigg),
$$
...
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Rate of polymerization for copolymers with two monomers
I've found in textbooks that for a chain growth homopolymerization the rate of polymerization $r_\mathrm{p}$ is
$$r_\mathrm{p} = k_\mathrm{p}\sqrt{\frac{f_\mathrm{kd}}{k_\mathrm{t}}}c_\ce{A}^ac_\ce{B}^...
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4
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What effect would decreasing melt viscosity by increasing melt temperature have on filler disaggregation in an extruder/compounder?
PLA has a melting point of around 150-160 degrees Celcius (the grade I am working with). I have microcellulosic fillers with aspect ratios that I am introducing to the polymer for compounding in a ...
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