SlideShare uma empresa Scribd logo
1 de 25
Baixar para ler offline
IN THE NAME OF GOD

SUBJECT:
Hydrolytic Degradation
Hydrolytic Degradation:
 This

process occurs in polymers that are watersensitive active groups, especially those that
take a lot of moisture.
 Polymers that have an ability for hydrolytic
destruction usually have heteroatoms in the
main or side chain.
hydrolysis :
the scission of chemical functional groups by
reaction with water. some polymers are very stable
to hydrolysis
Hydrolytic degradation
Water Absorption
 Plastics

absorb water to varying
degrees, depending on their molecular
structure, fillers and additives
 Adversely affects both mechanical and
electrical properties and causes swelling
 Measures the amount of water absorbed
as a percent of total weight
 Exposing

plastics to moisture at
elevated temperature can lead to
hydrolysis
A

chemical process that severs polymer
chains by reacting with water
 Reduces the molecular weight and
degrades the plastic
 Degree

of degradation depends on

 Exposure

time
 Temperature
 Stress levels
 degradation












rate dependent on

hydrophobicity
crystallinity
Tg
impurities
initial molecular weight, polydispersity
degree of crosslinking
manufacturing procedure
geometry
site of implantation
 Hydrolytic

Degradation can also be
harmful and helpful in cases, for example:

Hydrolytic chain scission of the ester linkage
of polyester is the fastest and the most
“harmful” degradation process, as it causes
a considerable reduction in the molecular
weight and in the mechanical properties of
the polymer. but The polymer degradation
useful for Controlled Drug Delivery System
For most biodegradable
materials, especially artificial
polymers, passive hydrolysis is the most
important kind of degradation . There are
several factors that influence the velocity of
this reaction; the most important are:
 type of chemical bond
 PH
 copolymer composition
 water uptake
 morphology
Hydrolysis tests


The hydrolytic degradation test was
performed in a basic aqueos solution at pH
12.7 at 50 °C. Each sample was in kept in a
sealed container with 50 ml of solution. The
degradation media was changed regularly so
that the pH was maintained and polymer
matrix samples were taken after time intervals.
Degraded specimens were collected at
desired intervals and dried for 24 h in a
vacuum oven at room temperature, and then
the weight loss was measured
Hydrolytic Degradation Behavior of Biodegradable
Polymers from Controlled Drug Delivery System:


There are different types of polymer degradation
such as photo, thermal, mechanical and
chemical degradation. For in-vivo application;
thermal degradation is not of much significance.
biodegradable polymers contain hydrolysable
bonds making them more prone to chemical
degradation via hydrolysis or enzyme-catalyzed
hydrolysis. Enzymatic degradation does not play
significant role in polymers belonging to
lactide/glycolide family. Therefore, study of
hydrolytic degradation is utmost important while
considering performance of polymeric implants
or polymeric drug delivery system.
Mechanism of Polymer
Degradation and Erosion:


The difference between polymer “degradation“
and “erosion“ is not clear in many cases.
Biodegradable polymers undergo hydrolytic
bond cleavage to form water soluble
degradation products that can dissolve in an
aqueous environment, resulting in polymer
erosion . In this context, degradation is a
chemical phenomenon and erosion
encompasses physical phenomena, such as
dissolution and diffusion. Polymer degradation is
the key route of erosion.


Polymer erosion is so far more complex than
degradation, because it depends on many
other processes, such as
degradation, swelling, dissolution and
diffusion of oligomers and monomers, and
morphological changes. The erosion of a
polymer matrix can proceed through two
alternative physical mechanisms: (a) surface
erosion and (b) bulk erosion. For ideal surface
erosion, erosion rate is constant and
proportional to external surface area. For bulk
eroding polymers such as PLA and
PLGA, things are more complicated as they
have no constant erosion rate
 One

is homogeneous or bulk erosion, in which
hydrolysis occurs simultaneously throughout
the entire specimen.Hence, the decrease in
molecular weight, the reduction in mechanical
properties, and the loss of mass also occur
throughout the entire specimen at the same
pace. Polymers containing ester, ether, and
amide groups, such as poly(lactic acid)
(PLA), poly(glycolic acid), poly(εcaprolactone), polyamide, proteins, and
cellulose (and its derivatives), generally exhibit
this type of erosion.
 These

reactions can sometimes be catalyzed
by the polymers’ own hydrolysis products.
The other type is heterogeneous or surface
erosion, in which hydrolysis mainly occurs in
the region near the surface, whereas the
bulk material is only slightly or not at all
hydrolyzed. As the surface is eroded and
removed. Polymers such as poly(ortho ester)s
(POEs), PAHs, and some polycarbonates
tend to undergo surface erosion.
Hydrolytic degradation
Mechanism of Hydrolytic Degradation
 Hydrolytic

degradation of members of the
polylactide/glycolide family proceeds through
four stages as represented in Figure 2: First
stage of water diffusion followed by second
stage, in which oligomers with acidic endgroups autocatalyze the hydrolysis reaction. A
critical molecular weight is reached at the
beginning of third stage,and oligomers start to
diffuse out from the polymer. Water molecules
diffuse into the void created by the removal of
the oligomers, which in turn encourages
oligomers diffusion.
 Marked

decrease in polymer mass and a
sharp increase in the drug release rate occur
during third stage as the drug diffuses from
the porous regions. In fourth stage, polymeric
matrix become highly porous and
degradation proceeds homogeneously and
more slowly .
Hydrolytic degradation
Factors Influencing Polymer
Degradation:


In recent years a number of parameters have
been identified that influence the polymer
degradation. Among them are the
copolymer composition
, morphology, autocatalysis by acidic
degradation products inside a matrix
, presence of drugs or other excipients and
preparation technique. However, the impacts
of these parameters that increase or
decrease the degradation rate are not
exactly clear. Review on effect of various
factors on polymer degradation is presented
in Table 1.
Hydrolytic degradation
Hydrolytic Degradation Behavior of Poly(butylene
succinate)s with Different Crystalline Morphologies
 The

effects of crystallinity and morphology on
polymer hydrolysis were studied for a decade.
It is known that hydrolytic degradation
proceeds at a higher rate in the amorphous
region than in the crystalline region. The higher
degradation rate in the amorphous region is
attributed to the easy diffusion of water
molecules into the interior of polymers.
Hydrolytic degradation
Techniques Used to Study
Polymer Degradation:
 Hydrolytic

degradation and erosion were
then followed through time by FTIR
spectroscopy and weight loss
measurements. In the solid state, titration of
acid end group, infrared (IR) spectroscopy
and intrinsic viscosity were used to analyze
the hydrolytic degradation in order to define
the degradation rate.
Hydrolytic degradation
REFERENCES:
 http://www.sbaoi.org.
 CHARACTERIZATION AND DEGRADATION

MECHANISMS OF ALIPHATIC POLYESTERS.
 Degradation as a Method of Modification of Polymeric
Products.
 From Wikipedia, the free encyclopedia
 www.sciencedirect.com

Mais conteúdo relacionado

Mais procurados

Mais procurados (20)

Polymers
Polymers Polymers
Polymers
 
Hydrogels
Hydrogels Hydrogels
Hydrogels
 
Additives
AdditivesAdditives
Additives
 
Plasticizer class ppt
Plasticizer class pptPlasticizer class ppt
Plasticizer class ppt
 
Polymers
PolymersPolymers
Polymers
 
Polymer and polymer synthesis
Polymer and polymer synthesisPolymer and polymer synthesis
Polymer and polymer synthesis
 
Polymer Additives and Blends
Polymer Additives and Blends Polymer Additives and Blends
Polymer Additives and Blends
 
Suspension polymerization
Suspension polymerizationSuspension polymerization
Suspension polymerization
 
Additives of Polymer, Additives of plastic, Improve properties of Plastic, Ty...
Additives of Polymer, Additives of plastic, Improve properties of Plastic, Ty...Additives of Polymer, Additives of plastic, Improve properties of Plastic, Ty...
Additives of Polymer, Additives of plastic, Improve properties of Plastic, Ty...
 
Emulsion polymerization
Emulsion polymerizationEmulsion polymerization
Emulsion polymerization
 
Coating chemistry
Coating chemistryCoating chemistry
Coating chemistry
 
emision polymerization
emision polymerizationemision polymerization
emision polymerization
 
Polymer Rheology(Properties study of polymer)
Polymer Rheology(Properties study of polymer)Polymer Rheology(Properties study of polymer)
Polymer Rheology(Properties study of polymer)
 
Mechanism of Polymerization
Mechanism of Polymerization Mechanism of Polymerization
Mechanism of Polymerization
 
Polymerization techniques
Polymerization techniquesPolymerization techniques
Polymerization techniques
 
Poly lactic acid
Poly lactic acidPoly lactic acid
Poly lactic acid
 
Mode of drug degradation of drugs
Mode of drug degradation of drugsMode of drug degradation of drugs
Mode of drug degradation of drugs
 
Polypropylene
PolypropylenePolypropylene
Polypropylene
 
Miscibility and Thermodynamics of Polymer Blends
Miscibility and Thermodynamics of Polymer BlendsMiscibility and Thermodynamics of Polymer Blends
Miscibility and Thermodynamics of Polymer Blends
 
08.hm adhesives and appln
08.hm adhesives and appln08.hm adhesives and appln
08.hm adhesives and appln
 

Destaque (20)

Thermal degradation ppt of polymers
Thermal degradation ppt of polymersThermal degradation ppt of polymers
Thermal degradation ppt of polymers
 
Types of polymer degradation
Types of polymer degradationTypes of polymer degradation
Types of polymer degradation
 
Recycling & degradation of polymers.
Recycling  & degradation of polymers.Recycling  & degradation of polymers.
Recycling & degradation of polymers.
 
Hydrolysis
HydrolysisHydrolysis
Hydrolysis
 
Presentation on photo degradation and photo stabilization of polymers
Presentation on photo degradation and photo stabilization of polymersPresentation on photo degradation and photo stabilization of polymers
Presentation on photo degradation and photo stabilization of polymers
 
Polymers evs ppt (3)
Polymers evs ppt (3)Polymers evs ppt (3)
Polymers evs ppt (3)
 
Hydrolysis
HydrolysisHydrolysis
Hydrolysis
 
Thermal Degradation of PMMA
Thermal Degradation of PMMAThermal Degradation of PMMA
Thermal Degradation of PMMA
 
Salt hydrolysis
Salt hydrolysisSalt hydrolysis
Salt hydrolysis
 
Polymer architecture
Polymer architecture Polymer architecture
Polymer architecture
 
PMMA
PMMAPMMA
PMMA
 
biodegradable polymers
biodegradable polymersbiodegradable polymers
biodegradable polymers
 
Drug delivery
Drug deliveryDrug delivery
Drug delivery
 
Apllication of tga
Apllication of tgaApllication of tga
Apllication of tga
 
Corrosion and degradation of materials
Corrosion and degradation of materialsCorrosion and degradation of materials
Corrosion and degradation of materials
 
App phys chem 5 polymer chemistry
App phys chem 5 polymer chemistryApp phys chem 5 polymer chemistry
App phys chem 5 polymer chemistry
 
Corrosion
CorrosionCorrosion
Corrosion
 
Biodegradable polymeric delivery system
Biodegradable polymeric delivery systemBiodegradable polymeric delivery system
Biodegradable polymeric delivery system
 
Biodegradation
BiodegradationBiodegradation
Biodegradation
 
acid base catalysed Ester hydrolysis
acid base catalysed Ester hydrolysisacid base catalysed Ester hydrolysis
acid base catalysed Ester hydrolysis
 

Semelhante a Hydrolytic degradation

Natural and Biodegradable polymers.pptx
Natural and  Biodegradable polymers.pptxNatural and  Biodegradable polymers.pptx
Natural and Biodegradable polymers.pptxDharmendra Chaudhary
 
Physicochemical properties affecting bioequivalence studies
Physicochemical properties affecting bioequivalence studiesPhysicochemical properties affecting bioequivalence studies
Physicochemical properties affecting bioequivalence studiesAadityaThole
 
Biodegradable polymers
Biodegradable polymersBiodegradable polymers
Biodegradable polymersMalay Jivani
 
Stability Of Peptides And Proteins
Stability Of Peptides And ProteinsStability Of Peptides And Proteins
Stability Of Peptides And ProteinsThilak Chandra
 
degradable polymeric carriers for parenteral controlled drug delivery
degradable polymeric carriers for parenteral controlled drug deliverydegradable polymeric carriers for parenteral controlled drug delivery
degradable polymeric carriers for parenteral controlled drug deliveryOmer Mustapha
 
Biodegradation of polymers group 2
Biodegradation of polymers group 2Biodegradation of polymers group 2
Biodegradation of polymers group 2helmi10
 
Physico-chemical Properties Affecting Drug Formulation.
Physico-chemical Properties Affecting Drug Formulation.Physico-chemical Properties Affecting Drug Formulation.
Physico-chemical Properties Affecting Drug Formulation.Muavia Sarwar
 
PLGA Role in Biopharmaceutics
PLGA Role in Biopharmaceutics PLGA Role in Biopharmaceutics
PLGA Role in Biopharmaceutics Dr.Ali Hussein
 
Drug degradation
Drug degradationDrug degradation
Drug degradationAmeenah
 
4_2018_03_07!07_18_04_AM.pptx
4_2018_03_07!07_18_04_AM.pptx4_2018_03_07!07_18_04_AM.pptx
4_2018_03_07!07_18_04_AM.pptxmehreenrehman2
 
Polymers Used In Pharmaceutical dosage delivery systems
Polymers Used In Pharmaceutical dosage delivery systemsPolymers Used In Pharmaceutical dosage delivery systems
Polymers Used In Pharmaceutical dosage delivery systemsHeenaParveen23
 

Semelhante a Hydrolytic degradation (20)

Natural and Biodegradable polymers.pptx
Natural and  Biodegradable polymers.pptxNatural and  Biodegradable polymers.pptx
Natural and Biodegradable polymers.pptx
 
Physicochemical properties affecting bioequivalence studies
Physicochemical properties affecting bioequivalence studiesPhysicochemical properties affecting bioequivalence studies
Physicochemical properties affecting bioequivalence studies
 
Biodegradable polymers
Biodegradable polymersBiodegradable polymers
Biodegradable polymers
 
Biodegradable Polymers
Biodegradable PolymersBiodegradable Polymers
Biodegradable Polymers
 
Drug stability
Drug stabilityDrug stability
Drug stability
 
Biodegradation
BiodegradationBiodegradation
Biodegradation
 
Stability Of Peptides And Proteins
Stability Of Peptides And ProteinsStability Of Peptides And Proteins
Stability Of Peptides And Proteins
 
degradable polymeric carriers for parenteral controlled drug delivery
degradable polymeric carriers for parenteral controlled drug deliverydegradable polymeric carriers for parenteral controlled drug delivery
degradable polymeric carriers for parenteral controlled drug delivery
 
Biodegradation of polymers group 2
Biodegradation of polymers group 2Biodegradation of polymers group 2
Biodegradation of polymers group 2
 
Physico-chemical Properties Affecting Drug Formulation.
Physico-chemical Properties Affecting Drug Formulation.Physico-chemical Properties Affecting Drug Formulation.
Physico-chemical Properties Affecting Drug Formulation.
 
Polymer science
Polymer science Polymer science
Polymer science
 
Gels
GelsGels
Gels
 
Biodegradable polymers
Biodegradable polymersBiodegradable polymers
Biodegradable polymers
 
PLGA Role in Biopharmaceutics
PLGA Role in Biopharmaceutics PLGA Role in Biopharmaceutics
PLGA Role in Biopharmaceutics
 
Drug degradation
Drug degradationDrug degradation
Drug degradation
 
Biodegradable Polymers
Biodegradable PolymersBiodegradable Polymers
Biodegradable Polymers
 
Assignment
AssignmentAssignment
Assignment
 
Assignment
AssignmentAssignment
Assignment
 
4_2018_03_07!07_18_04_AM.pptx
4_2018_03_07!07_18_04_AM.pptx4_2018_03_07!07_18_04_AM.pptx
4_2018_03_07!07_18_04_AM.pptx
 
Polymers Used In Pharmaceutical dosage delivery systems
Polymers Used In Pharmaceutical dosage delivery systemsPolymers Used In Pharmaceutical dosage delivery systems
Polymers Used In Pharmaceutical dosage delivery systems
 

Último

UiPath Solutions Management Preview - Northern CA Chapter - March 22.pdf
UiPath Solutions Management Preview - Northern CA Chapter - March 22.pdfUiPath Solutions Management Preview - Northern CA Chapter - March 22.pdf
UiPath Solutions Management Preview - Northern CA Chapter - March 22.pdfDianaGray10
 
Introduction to Matsuo Laboratory (ENG).pptx
Introduction to Matsuo Laboratory (ENG).pptxIntroduction to Matsuo Laboratory (ENG).pptx
Introduction to Matsuo Laboratory (ENG).pptxMatsuo Lab
 
Using IESVE for Loads, Sizing and Heat Pump Modeling to Achieve Decarbonization
Using IESVE for Loads, Sizing and Heat Pump Modeling to Achieve DecarbonizationUsing IESVE for Loads, Sizing and Heat Pump Modeling to Achieve Decarbonization
Using IESVE for Loads, Sizing and Heat Pump Modeling to Achieve DecarbonizationIES VE
 
Salesforce Miami User Group Event - 1st Quarter 2024
Salesforce Miami User Group Event - 1st Quarter 2024Salesforce Miami User Group Event - 1st Quarter 2024
Salesforce Miami User Group Event - 1st Quarter 2024SkyPlanner
 
Connector Corner: Extending LLM automation use cases with UiPath GenAI connec...
Connector Corner: Extending LLM automation use cases with UiPath GenAI connec...Connector Corner: Extending LLM automation use cases with UiPath GenAI connec...
Connector Corner: Extending LLM automation use cases with UiPath GenAI connec...DianaGray10
 
Computer 10: Lesson 10 - Online Crimes and Hazards
Computer 10: Lesson 10 - Online Crimes and HazardsComputer 10: Lesson 10 - Online Crimes and Hazards
Computer 10: Lesson 10 - Online Crimes and HazardsSeth Reyes
 
COMPUTER 10 Lesson 8 - Building a Website
COMPUTER 10 Lesson 8 - Building a WebsiteCOMPUTER 10 Lesson 8 - Building a Website
COMPUTER 10 Lesson 8 - Building a Websitedgelyza
 
20230202 - Introduction to tis-py
20230202 - Introduction to tis-py20230202 - Introduction to tis-py
20230202 - Introduction to tis-pyJamie (Taka) Wang
 
AI You Can Trust - Ensuring Success with Data Integrity Webinar
AI You Can Trust - Ensuring Success with Data Integrity WebinarAI You Can Trust - Ensuring Success with Data Integrity Webinar
AI You Can Trust - Ensuring Success with Data Integrity WebinarPrecisely
 
9 Steps For Building Winning Founding Team
9 Steps For Building Winning Founding Team9 Steps For Building Winning Founding Team
9 Steps For Building Winning Founding TeamAdam Moalla
 
UiPath Studio Web workshop series - Day 6
UiPath Studio Web workshop series - Day 6UiPath Studio Web workshop series - Day 6
UiPath Studio Web workshop series - Day 6DianaGray10
 
NIST Cybersecurity Framework (CSF) 2.0 Workshop
NIST Cybersecurity Framework (CSF) 2.0 WorkshopNIST Cybersecurity Framework (CSF) 2.0 Workshop
NIST Cybersecurity Framework (CSF) 2.0 WorkshopBachir Benyammi
 
Meet the new FSP 3000 M-Flex800™
Meet the new FSP 3000 M-Flex800™Meet the new FSP 3000 M-Flex800™
Meet the new FSP 3000 M-Flex800™Adtran
 
Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...
Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...
Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...Will Schroeder
 
Basic Building Blocks of Internet of Things.
Basic Building Blocks of Internet of Things.Basic Building Blocks of Internet of Things.
Basic Building Blocks of Internet of Things.YounusS2
 
UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...
UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...
UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...UbiTrack UK
 
OpenShift Commons Paris - Choose Your Own Observability Adventure
OpenShift Commons Paris - Choose Your Own Observability AdventureOpenShift Commons Paris - Choose Your Own Observability Adventure
OpenShift Commons Paris - Choose Your Own Observability AdventureEric D. Schabell
 
Nanopower In Semiconductor Industry.pdf
Nanopower  In Semiconductor Industry.pdfNanopower  In Semiconductor Industry.pdf
Nanopower In Semiconductor Industry.pdfPedro Manuel
 

Último (20)

UiPath Solutions Management Preview - Northern CA Chapter - March 22.pdf
UiPath Solutions Management Preview - Northern CA Chapter - March 22.pdfUiPath Solutions Management Preview - Northern CA Chapter - March 22.pdf
UiPath Solutions Management Preview - Northern CA Chapter - March 22.pdf
 
Introduction to Matsuo Laboratory (ENG).pptx
Introduction to Matsuo Laboratory (ENG).pptxIntroduction to Matsuo Laboratory (ENG).pptx
Introduction to Matsuo Laboratory (ENG).pptx
 
Using IESVE for Loads, Sizing and Heat Pump Modeling to Achieve Decarbonization
Using IESVE for Loads, Sizing and Heat Pump Modeling to Achieve DecarbonizationUsing IESVE for Loads, Sizing and Heat Pump Modeling to Achieve Decarbonization
Using IESVE for Loads, Sizing and Heat Pump Modeling to Achieve Decarbonization
 
Salesforce Miami User Group Event - 1st Quarter 2024
Salesforce Miami User Group Event - 1st Quarter 2024Salesforce Miami User Group Event - 1st Quarter 2024
Salesforce Miami User Group Event - 1st Quarter 2024
 
Connector Corner: Extending LLM automation use cases with UiPath GenAI connec...
Connector Corner: Extending LLM automation use cases with UiPath GenAI connec...Connector Corner: Extending LLM automation use cases with UiPath GenAI connec...
Connector Corner: Extending LLM automation use cases with UiPath GenAI connec...
 
Computer 10: Lesson 10 - Online Crimes and Hazards
Computer 10: Lesson 10 - Online Crimes and HazardsComputer 10: Lesson 10 - Online Crimes and Hazards
Computer 10: Lesson 10 - Online Crimes and Hazards
 
201610817 - edge part1
201610817 - edge part1201610817 - edge part1
201610817 - edge part1
 
20230104 - machine vision
20230104 - machine vision20230104 - machine vision
20230104 - machine vision
 
COMPUTER 10 Lesson 8 - Building a Website
COMPUTER 10 Lesson 8 - Building a WebsiteCOMPUTER 10 Lesson 8 - Building a Website
COMPUTER 10 Lesson 8 - Building a Website
 
20230202 - Introduction to tis-py
20230202 - Introduction to tis-py20230202 - Introduction to tis-py
20230202 - Introduction to tis-py
 
AI You Can Trust - Ensuring Success with Data Integrity Webinar
AI You Can Trust - Ensuring Success with Data Integrity WebinarAI You Can Trust - Ensuring Success with Data Integrity Webinar
AI You Can Trust - Ensuring Success with Data Integrity Webinar
 
9 Steps For Building Winning Founding Team
9 Steps For Building Winning Founding Team9 Steps For Building Winning Founding Team
9 Steps For Building Winning Founding Team
 
UiPath Studio Web workshop series - Day 6
UiPath Studio Web workshop series - Day 6UiPath Studio Web workshop series - Day 6
UiPath Studio Web workshop series - Day 6
 
NIST Cybersecurity Framework (CSF) 2.0 Workshop
NIST Cybersecurity Framework (CSF) 2.0 WorkshopNIST Cybersecurity Framework (CSF) 2.0 Workshop
NIST Cybersecurity Framework (CSF) 2.0 Workshop
 
Meet the new FSP 3000 M-Flex800™
Meet the new FSP 3000 M-Flex800™Meet the new FSP 3000 M-Flex800™
Meet the new FSP 3000 M-Flex800™
 
Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...
Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...
Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...
 
Basic Building Blocks of Internet of Things.
Basic Building Blocks of Internet of Things.Basic Building Blocks of Internet of Things.
Basic Building Blocks of Internet of Things.
 
UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...
UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...
UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...
 
OpenShift Commons Paris - Choose Your Own Observability Adventure
OpenShift Commons Paris - Choose Your Own Observability AdventureOpenShift Commons Paris - Choose Your Own Observability Adventure
OpenShift Commons Paris - Choose Your Own Observability Adventure
 
Nanopower In Semiconductor Industry.pdf
Nanopower  In Semiconductor Industry.pdfNanopower  In Semiconductor Industry.pdf
Nanopower In Semiconductor Industry.pdf
 

Hydrolytic degradation

  • 1. IN THE NAME OF GOD SUBJECT: Hydrolytic Degradation
  • 2. Hydrolytic Degradation:  This process occurs in polymers that are watersensitive active groups, especially those that take a lot of moisture.  Polymers that have an ability for hydrolytic destruction usually have heteroatoms in the main or side chain. hydrolysis : the scission of chemical functional groups by reaction with water. some polymers are very stable to hydrolysis
  • 4. Water Absorption  Plastics absorb water to varying degrees, depending on their molecular structure, fillers and additives  Adversely affects both mechanical and electrical properties and causes swelling  Measures the amount of water absorbed as a percent of total weight
  • 5.  Exposing plastics to moisture at elevated temperature can lead to hydrolysis A chemical process that severs polymer chains by reacting with water  Reduces the molecular weight and degrades the plastic  Degree of degradation depends on  Exposure time  Temperature  Stress levels
  • 6.  degradation          rate dependent on hydrophobicity crystallinity Tg impurities initial molecular weight, polydispersity degree of crosslinking manufacturing procedure geometry site of implantation
  • 7.  Hydrolytic Degradation can also be harmful and helpful in cases, for example: Hydrolytic chain scission of the ester linkage of polyester is the fastest and the most “harmful” degradation process, as it causes a considerable reduction in the molecular weight and in the mechanical properties of the polymer. but The polymer degradation useful for Controlled Drug Delivery System
  • 8. For most biodegradable materials, especially artificial polymers, passive hydrolysis is the most important kind of degradation . There are several factors that influence the velocity of this reaction; the most important are:  type of chemical bond  PH  copolymer composition  water uptake  morphology
  • 9. Hydrolysis tests  The hydrolytic degradation test was performed in a basic aqueos solution at pH 12.7 at 50 °C. Each sample was in kept in a sealed container with 50 ml of solution. The degradation media was changed regularly so that the pH was maintained and polymer matrix samples were taken after time intervals. Degraded specimens were collected at desired intervals and dried for 24 h in a vacuum oven at room temperature, and then the weight loss was measured
  • 10. Hydrolytic Degradation Behavior of Biodegradable Polymers from Controlled Drug Delivery System:  There are different types of polymer degradation such as photo, thermal, mechanical and chemical degradation. For in-vivo application; thermal degradation is not of much significance. biodegradable polymers contain hydrolysable bonds making them more prone to chemical degradation via hydrolysis or enzyme-catalyzed hydrolysis. Enzymatic degradation does not play significant role in polymers belonging to lactide/glycolide family. Therefore, study of hydrolytic degradation is utmost important while considering performance of polymeric implants or polymeric drug delivery system.
  • 11. Mechanism of Polymer Degradation and Erosion:  The difference between polymer “degradation“ and “erosion“ is not clear in many cases. Biodegradable polymers undergo hydrolytic bond cleavage to form water soluble degradation products that can dissolve in an aqueous environment, resulting in polymer erosion . In this context, degradation is a chemical phenomenon and erosion encompasses physical phenomena, such as dissolution and diffusion. Polymer degradation is the key route of erosion.
  • 12.  Polymer erosion is so far more complex than degradation, because it depends on many other processes, such as degradation, swelling, dissolution and diffusion of oligomers and monomers, and morphological changes. The erosion of a polymer matrix can proceed through two alternative physical mechanisms: (a) surface erosion and (b) bulk erosion. For ideal surface erosion, erosion rate is constant and proportional to external surface area. For bulk eroding polymers such as PLA and PLGA, things are more complicated as they have no constant erosion rate
  • 13.  One is homogeneous or bulk erosion, in which hydrolysis occurs simultaneously throughout the entire specimen.Hence, the decrease in molecular weight, the reduction in mechanical properties, and the loss of mass also occur throughout the entire specimen at the same pace. Polymers containing ester, ether, and amide groups, such as poly(lactic acid) (PLA), poly(glycolic acid), poly(εcaprolactone), polyamide, proteins, and cellulose (and its derivatives), generally exhibit this type of erosion.
  • 14.  These reactions can sometimes be catalyzed by the polymers’ own hydrolysis products. The other type is heterogeneous or surface erosion, in which hydrolysis mainly occurs in the region near the surface, whereas the bulk material is only slightly or not at all hydrolyzed. As the surface is eroded and removed. Polymers such as poly(ortho ester)s (POEs), PAHs, and some polycarbonates tend to undergo surface erosion.
  • 16. Mechanism of Hydrolytic Degradation  Hydrolytic degradation of members of the polylactide/glycolide family proceeds through four stages as represented in Figure 2: First stage of water diffusion followed by second stage, in which oligomers with acidic endgroups autocatalyze the hydrolysis reaction. A critical molecular weight is reached at the beginning of third stage,and oligomers start to diffuse out from the polymer. Water molecules diffuse into the void created by the removal of the oligomers, which in turn encourages oligomers diffusion.
  • 17.  Marked decrease in polymer mass and a sharp increase in the drug release rate occur during third stage as the drug diffuses from the porous regions. In fourth stage, polymeric matrix become highly porous and degradation proceeds homogeneously and more slowly .
  • 19. Factors Influencing Polymer Degradation:  In recent years a number of parameters have been identified that influence the polymer degradation. Among them are the copolymer composition , morphology, autocatalysis by acidic degradation products inside a matrix , presence of drugs or other excipients and preparation technique. However, the impacts of these parameters that increase or decrease the degradation rate are not exactly clear. Review on effect of various factors on polymer degradation is presented in Table 1.
  • 21. Hydrolytic Degradation Behavior of Poly(butylene succinate)s with Different Crystalline Morphologies  The effects of crystallinity and morphology on polymer hydrolysis were studied for a decade. It is known that hydrolytic degradation proceeds at a higher rate in the amorphous region than in the crystalline region. The higher degradation rate in the amorphous region is attributed to the easy diffusion of water molecules into the interior of polymers.
  • 23. Techniques Used to Study Polymer Degradation:  Hydrolytic degradation and erosion were then followed through time by FTIR spectroscopy and weight loss measurements. In the solid state, titration of acid end group, infrared (IR) spectroscopy and intrinsic viscosity were used to analyze the hydrolytic degradation in order to define the degradation rate.
  • 25. REFERENCES:  http://www.sbaoi.org.  CHARACTERIZATION AND DEGRADATION MECHANISMS OF ALIPHATIC POLYESTERS.  Degradation as a Method of Modification of Polymeric Products.  From Wikipedia, the free encyclopedia  www.sciencedirect.com