Implementation of Innovative Actions & Future Suggestion
Implementation of Innovative Actions & Future Suggestion
I. How a small thin O Ring stalls Motorcycle
One of the leading two wheeler manufacturer in India observed that the FKM component is changing in volume & other properties with each successive exposure to atmospheric Heat & Gasoline fumes. According to them with the first exposure certain volumetric expansion takes place ( X ) and then when the part is kept out (dried in atmosphere) it does not return to it’s original state. In the second exposure it starts swelling again from an already swollen state. If in stage 2 the swelling is Y, the total swelling shall be X + Y”.
A swollen FKM ( or any Elastomer ) product will take very long period to dry but it can never come to its zero position , will be very close to zero. Question is after what period that stage will reach. These factors need to be kept in mind while designing the item.
This causes fuel vapour leakage
stalling of Engine.
Swelling characteristic is linked to
“Mass” (in turn thickness in this case)
This is explained below mathematical
formulation.
SW
α P * PC *
SOL * µ * T * SH *
CD * (DIM) --------
TH
SW – Swelling / P – Polymer type / PC – Polymer
content / SOL – Solvent / T –
Temperature
SH – Hardness (SH-A) / CD –
Crosslink Density / DIM (Dimension) –
Represented by Thickness ( TH )
µ - Interaction constant
characteristic of the rubber and swelling liquid
In a particular case
P / PC / SOL / T / SH / CD /
µ are constant
1
SW α
TH
1
Using logarithm system Log SW
= Log
TH
Assuring Thickness changing form TH1 ……………… TH5, Plot of these
two dimension should indicate Swelling behavior with Thickness change.
II. How much Tyres contribute to PM in the
Environment
Study on the Impact of tyre usage on Environment – Indian
perspective
It is the Tread of a Tyre wears , which is made of rubbers /
reinforcing agents (fillers) Processing aids / Softeners (Process oils) /
number of Chemicals , waxes. These (except Silica & Zinc oxide) are all
Petroproducts.
While running of a vehicle tyre has to provide friction
(grip) to the road enabling the vehicle to roll and provide steering &
braking effect and minimum Rolling resistance to reduce drag on engine &
in-turn lower fuel consumption – the major polluting factor. During drive tyre
abrades, NSD ( Non Skid Depth ) reduces to a point when the tyre is no more
safe to drive due to different factors. This NSD varies strongly depending on
tyre size & type & application.
Tyre abrades & NSD reduces – where do the worn tyre
material goes ? Obviously to the atmosphere, rubbers & chemicals particles
flow in the air (Particulate matter – size ?) which we inhale. Many of these
Petroproducts are restricted under REACH and other laws and most of these are
taken care of by the technologist. But not all.
Rubber Loss (debris / particle in
environment) caused by wear of the tyre may be represented by the following
relationship.
R L α (TR0 – TR1) ·
(AI ·KM ·t · tan δ · RR ) X C
Considering ( AI, KM, t, tan δ
& RR) constant for a particular tyre run, R L is then related to wear .
i.e R L α C ·(TR0 – TR1).
R L – Robber Loss
TR0 - Tread Original NSD
TR1 - Tread
NSD at remaining NSD (say 2 m for CV)
AI – Abrasion
Index
KM - Kilometre
run
t - time
of run
tan δ - Heat
development of the tyre
RR - Rolling
Resistance
C - Constant
(related to drive stretch / Vehicle & Load / Driving character /
atmosphere condition etc.)
Or R L α C ·(x . TW) / TR0
where x = (TR0 – TR1)
in mm and TW is Tread wright of that particular tyre.
Tyre Production for 2015-16 and other Data Information
for Calculation of Rubber Loss
Table II
How may ingredients used in tyre compound attract REACH regulation? Extensive list of chemicals restricted under REACH is available in the literature. Next most important question is – can these be restricted / reduced and if so, how?
1. Developing highly wear resistant compound – internationally most of the tyre companies are pursuing R&D in this direction. How much Indian tyre companies are active in this direction need to be made public.
2. Thus, reduce quantum of material usage.
3. Replace petro based ingredients – mainly CB & process oil – already in process of using Silica and PAH free process oil. Technical properties and cost factor to be watched.
Chemical Loss from CV Tyre Tread, Cross Ply Lug type - Typical compound formulation, average tread weight 22 Kg
Table III
Tyre Tread (Rubber) Loss
Table II gives the basic calculation of tyre loss and waste
generation quantitative amount.
Total quantity of rubber loss adds up to 6756.83 MT. This
is excluding Tractor Tyre and OTR. Hence the total quantity would be
substantially higher than this. However, Tractor tyre & OTR are not for
use on road, they remain in agricultural & mining / construction area and
the particles generated from the usage of these tyres is small compared to
other dust / particles generated in these activities.
Out of considered total output, T / B accounts for nearly
90% of the quantity, LCV nearly 4.4%, Passenger 3% and 2/3-Wheeler about 3%.
Hence all concentration should be to T / B.
III. Vibration absorption of Washing
Machine (Rubber Foot)
Basic Vibration Terminology - Below some basic vibration terminology discussed to aid better understanding in subsequent section.
Natural
Frequency - Natural
frequency is the frequency at which a system tends
to oscillate in the absence of any driving
or damping force. It is the system property, it can be altered
by varying the mass, Stiffness and its damping.
Equation
for natural frequency of simple single degree of freedom undamped system is
given by,
Where k is
stiffness and m is mass of system.
Forcing Frequency - is the force applied on the system. It can be running speed, or a frequency transmitted from nearby member. Here it is rotating speed of drum.
When
forcing frequency (rotational speed of drum) matches with natural frequency of system resonance
occurs. Vibration of system increases
significantly, and it can cause failure of system if vibration is not dampened
out.
Transmissibility - It is a ratio of force transmitted to ground to exciting force to the system. Transmissibility should be should be as low as possible to reduce force transmitted to supporting structure.
Effect
of rubber foot properties on machine vibration
Effect
of Stiffness
• Natural frequencies of system
directly proportional to square root of stiffness. Similarly one of resonance
frequency of washing machine associated with foot is also proportional
stiffness of rubber foot.
• If resonance frequency of washing
machine falls near to operating region it will lead to severe vibration of
machine and over period of time it may cause fatigue failure of components.
• It is observed that natural
frequency (around 1320 RPM) associated with foot comes in operating frequency
of washing machine (up to 1400 RPM).
• So when rotational frequency of drum
matches with natural frequency, resonance occurs.
• To avoid resonance during operation
natural frequency should be kept outside operating region ( by increasing
stiffness as shown in figure)
Effect
of damping
• Damping has more effect on vibration
amplitude rather than natural frequency of the system.
• Moreover, effect of damping on
vibration amplitude varies with operating frequencies. Damping affects
vibration levels significantly near to resonance region while at higher
frequency there is negligible influence on vibration level.
• Here we are operating washing machine
near to one of resonance region associated with foot so higher damping in
rubber foot will help to reduce vibration level.
Effect
of damping on transmissibility
• To improve transmissibility, should
operate the system at greater than at least √2 times N.F. (black curve) which
needs to keep natural frequency as low as possible hence soft spring (K should
low) and low damping (black curve) so that N.F. can be shifted to low frequency
but this contradicts with earlier requirement ( to low vibration level, N.F.
should be higher than maximum operational frequency).
• Operating near resonance region
(less than √2 times N.F.) to reduce transmitted force it need to increase
damping property of foot material (green curve).
Dynamic
Mechanical Analysis of Rubber
In order to
characterize material damping (tan δ) and stiffness (dynamic stiffness)
properties in dynamic condition were carried out DMA (Dynamic mechanical
analysis) of different rubber material which with presented below.
- By selecting material having higher dynamic stiffness in desired operating range (15 Hz - 25 Hz) modal frequency can be increased and postpone outside operating region.
- From above plots of dynamic
stiffness of different rubber material at different frequencies, NBR SH 80
(Black & Grey) gave highest stiffness among all rubber composition in
desired frequency range (15 Hz - 25 Hz).
- Higher the tan δ of rubber,
higher the damping and lower the vibration amplitude so it is recommended
to select material having higher damping to reduce vibration level.
- From above plots of tan δ of different
rubber material at different frequencies, NBR SH 80 (Black) is giving
highest tan δ among all rubber composition in desired frequency range (15
Hz - 25 Hz).
Effect of
thickness and diameter of the rubber was studied using different thickness
level (3.0 & 3.5 mm) and diameter (30 & 34.5 mm) with radius of 215
& 160. Results are presented in following graphs. From these it is clear
that sample based on NBR with 3.5 thickness, 34.5 mm dia and 215 radius
provides the best damping characteristic.
Conclusion
From all
above analysis and results one can we concluded that NBR with shore hardness SH
– 80 is most suitable for washing machine foot application to reduce vibrations
and it will be 3.5 mm thickness 34.5 mm dia 215 roils use for further
development.
Effect
of Shore Hardness
- First and second modal frequencies of cabinet with different rubber material are plotted in above bar chart. Among all materials NBR - SH 80 and NR - SH 70 gives higher modal frequency due to higher stiffness of material. So from above results NR - SH 80 would give higher modal frequencies and better performance but NR can easily affects by chemical reaction which is not recommended.
- By comparing NBR-80- G (Grey) and NBR-80 (Black) it is observed that with black color modal frequencies are much higher than grey color due to higher content of carbon black. So it is recommended to select black rubber for washing machine foot application for vibration reduction.
- By comparing NBR-80-G and Butyl-80-G it is found that Butyl material will give higher modal frequencies hence lesser vibration than NBR. So if we developed Butyl SH 80 in black color it would give better performance but there are some practical limitation of Butyl over NBR i.e. higher cost, production difficulties, availability and productivity. So NBR is recommended over Butyl material.
Studies
on Adhesion – New Test Method for Measurement of Tack Modification of Peel Test
for Testing Rubber to Rubber joint
A new test
method has been developed to measure the autohesive tack between cap & base
compounds at higher temperature of contact. This method is a modification of
the 180° peel test by incorporating a separator or a perforated sheet at the
interface. This gives reproducing a results & simulates the co-extrusion
process at a relatively higher temperature of contact.
Use of
perforated sheet has two functions:
(1) It
prevents the tear from deviating from the interface or, in other words, it
guides the tear propagation process in the plane of the interface. The sharp
plastic sheet cuts the rubber when the tear deviates from the linear path.
(2) The
number of contact points can be counted and visualized during the test. As a
result, each peak force can be related to the number of contact points.
V. Ozonolysis & Amperometric Titration
innovative method to establish 1, 2 & 3, 4 NR structure.
First
Chemical (Method) Proof for 1, 2 & 3, 4 Structure of NR
Structure
of Natural Rubber has been established as -1, 4 Cis Polyisoprene long back.
Later, different instrumental studies, primarily IR Spectrophotometry, found
that a certain portion of NR has -1,2- structure. I took up the work to
identify the hydrolyzed ozonide NR products which resulted in Levulinic acid
and Formic acid. The fractions were separated by Column Chromatography followed
by estimation using Amperometry titration. This gave the evidence of – 1, 2-
and – 3, 4 – structure presence in NR besides main – 1, 4 – structure of
Polyisoprene.
Detection
of Formic & Acetic acid in Ozonolysis product besides Levulinic acid using
Paper & Column Chromatography with Silica gel column coupled with
Amperometry titration method showed that NR has –1, 2- or -3, 4- structure
besides predominant – 1, 4- structure. This was endorsed and the work was
published in UK Journal in 1962.
VI. Effect of moisture on Sulphenamide
accelerated CB compound
An
incidence with Internal Mixer
New
experience in the plant and development of technology enriched our knowledge.
When the chamber of one of the internal mixers was changed to new one, we
encountered unforeseen problem. Along with the master batch water droplets were
also falling on the dump-mill during discharge of the batch. Obviously, doubts
were that the water is coming from leakage somewhere in the machine. A thorough
check was conducted but no clue found.
arrangement
was made with BARC for short life radioactive Cobalt 60 which was mixed in the
closed loop of cooling water system of the mixer and circulated to find leakage
by testing radio activity of the water droplets.
No radio
activity was found on these water droplets. Finally, we could conclude that due
to improved cooling effect of the new chamber, moisture evaporating from rubber
and carbon black during mixing was condensing back causing water trace on the
master batch.
This
further led to the study – what will be the effect of moisture on sulphenamide
accelerators used in the compound which are sensitive to moisture, on the cure
characteristics of the compound. An elaborate study was carried out in
collaboration with Bayer India which resulted in publications in Kautschuk U
Gummi / Kunststoffe.
VII. Bio-Polymer
Biodegradation is a process, not an end result
IS / ISO
17088 (2008) provides
the specifications for compostable plastics.
Disintegration during composting
A plastic product is considered to have demonstrated
satisfactory disintegration if, after 84 days in a controlled composting test,
no more than 10 % of its original dry mass remains after sieving through a 2.0
mm sieve. The tests are carried out in accordance with ISO 16929, ISO 20200,
ISO 14855-1 or ASTM D 5338 under thermophilic composting conditions without CO2
trapping equipment.
Ultimate aerobic biodegradation
A plastic product is considered to have demonstrated a
satisfactory rate and level of biodegradation if when tested in accordance with
ISO 14855-1, ISO 14855-2 or ASTM D 5338, it achieves the ratio of conversion to
carbon dioxide specified (90% of organic carbon in the polymer) within the time
period specified (equal or less than 180 days).
Polyvinyl
Alcohol
Polyvinyl
alcohol (PVOH or PVA) is a water-soluble synthetic polymer.
PVA has excellent
film forming, emulsifying and adhesive properties.
PVA is also
resistant to oil, grease and solvents.
PVA has high
tensile strength and flexibility, as well as high oxygen and aroma barrier
properties.
However,
these properties are dependent on humidity
PVA has a
melting point of 230°C and 180 – 190°C for the fully hydrolyzed and partially
hydrolyzed grades respectively and decomposes rapidly above 200°C.
CORN
STARCH – PVA BLEND THERMOPLASTIC
Poly
(butylene adipate co-terephthalate)
PBAT is
a bio-degradable random co-polymer
Co-polyester
of adipic acid, 1,4 butanediol and terephthalic acid from dimethyl
terephthalate
Produced by
random co-polymerization of 1,4-butanediol, adipic acid, and dimethyl
terephthalate (DMT) monomers.
Main
advantage of PBAT is that it is a biodegradable alternative to LDPE,
having similar properties including high flexibility and toughness, allowing it
to be used for various packaging applications.
Polylactic Acid - PLA
Lactic acid
(2-hydroxypropionic acid) is the most widely occurring hydroxycarboxylic
optical active acid. Polylactide is based on lactic acid monomers obtained from
the fermentation of sugars obtained from renewable sources such as sugar cane
or corn starch.
Direct
polycondensation -
leads to low molecular weight polymers which then can be converted to higher
molecular weight polymers by addition of chain coupling agents.
Ring
opening polymerization - PLA is produced by formation of lactide monomer first and formed lactide
is then put through ROP using metal alkoxides as catalysts resulting in high
molecular weight polyester.
Market Potential
- No reliable statistics for the production or consumption of plastic bags in India.
- Proxy to estimate total consumption of plastic bags in India
- Plastic bags are mainly based on LDPE or low density polyethylene.
- Domestic LDPE consumption in 2016 - 17 was around 700,000 metric tons.
- Assuming 60% of total LDPE consumption was for the manufacture of plastic bags, the LDPE polymer consumption was be around 420,000 metric tons.
- Based on this figure, the consumption of LDPE compound for plastic bags will be around 600,000 metric tons.
- Even a 5% market share for bio-degradable material plastic bags represents a consumption figure of 30,000 metric tons per year growing at 20 to 25% year on year.
Global Scenario
VIII. ISOSORBIDE BASED POLYMER
Corn –
Starch – Glucose – Sorbitol – Isosorbide
I
TPU –
Excellent thermomechanical properties
Macromonomers
for TPU / PU
Aromatic
Polyester
Improved
temperature resistance
Excellent
clarity
Excellent
chemical resistance
Polycarbonate
Excellent Optical
properties
Chemical
& V resistance
High
temperature resistance
II Isosorbide in Polyester
Isosorbide
– 15 mol % - crystalline / Amorphus
5 & 10 mol % 15 mol & 20 mol %
Heat
resistance improves with Isosorbide mol % increase. Isosorbide increase Tg of
PET.
Isosorbide
in Polycarbonate
UV
stability
Better
compared to PC & PMMA
Suitable
for outdoor application
Excellent
dyeability, high gloss & scratch resistance
IX. ITACONIC ACID BASED POLYMER
Itaconic
acid is an
organic acid that is used as a platform chemical for the
production of various value added chemicals such as poly-itaconic acid,
resins biofuel components, ionomer cements etc. Itaconic acid and
its derivatives have wide applications in the textile,
chemical and pharmaceutical industries.
Dry
distillation of citric acid affords itaconic anhydride,
which undergoes hydrolysis to itaconic acid. Upon heating, itaconic
anhydride isomerizes to citraconic acid anhydride,
which can be hydrolyzed to citraconic acid (2-methylmaleic
acid).
Steps in conversion of citric acid to citraconic acid via
itaconic and aconitic
acids
Application
Itaconic acid is primarily used as a co-monomer in the
production of acrylonitrile
butadiene styrene and acrylate latexes with applications
in the paper and architectural coating industry.
X. New Concept of Waterless Washing Machine
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