Polymers in Preservation and Restoration: Two Examples

1996 ◽  
Vol 462 ◽  
Author(s):  
E.W. Merrill
Keyword(s):  
Volumetric Shrinkage ◽  
Polymer Particles ◽  
Acrylic Polymer ◽  
Vinyl Silane ◽  
Acrylic Monomers ◽  
Preservation And Restoration

ABSTRACTTwo ‘families’ of polymers applicable to preservation and restoration are discussed: (i) polysiloxane networks generated by platinum catalyzed addition of vinyl silane precursors to hydrogenosilane precursors; and (ii) acrylic compositions generated by redox initiated polymerization of acrylic monomers in the presence of fine spherical acrylic polymer particles. In both cases the end result is achieved at temperatures between ambient and 60°C, and with negligible volumetric shrinkage.

scholarly journals Nonwovens Containing Immobilized Superabsorbent Polymer Particles

2003 ◽  
Vol os-12 (3) ◽  
pp. 1558925003os-12
Author(s):  
Darryl L. Whitmore
Keyword(s):  
In Situ Polymerization ◽  
Ph Control ◽  
Personal Hygiene ◽  
Superabsorbent Polymer ◽  
Polymer Particles ◽  
Superabsorbent Polymers ◽  
Acrylic Monomers

In the early 1980's Johnson & Johnson developed a revolutionary process for the production of webs containing superabsorbent polymers (SAP) produced by in-situ polymerization of partially neutralized acrylic monomers directly on a synthetic nonwoven substrate [1, 2, 3, 4]. A fresh look at this forgotten technology will be presented from both a manufacturing and application perspective. In particular, In-situ, SAP-containing nonwovens offer many unique properties for application in the personal hygiene industry, such as, improved fluid acquisition, permeability, compressibility and pH control. These materials also provide a more homogenous SAP distribution, eliminate the need for SAP powder handling and have superior wet integrity as compared to conventional fluff pulp/SAP air laid structures. This technology also offers some unique opportunities for designing and manufacturing profiled absorbent articles with specific zones tailored to perform specific functions.

Uncontrolled polymerization that occurred during photoinitiated RAFT dispersion polymerization of acrylic monomers promotes the formation of uniform raspberry-like polymer particles

2020 ◽  
Vol 11 (28) ◽  
pp. 4591-4603 ◽  
Author(s):  
Ruiming Zeng ◽  
Ying Chen ◽  
Li Zhang ◽  
Jianbo Tan
Keyword(s):  
Dispersion Polymerization ◽  
Polymer Particles ◽  
Acrylic Monomers

Uniform raspberry-like polymer particles are prepared by a different type of photoinitiated RAFT dispersion polymerization.

Numerical Simulation on Dynamics and Thermal Decomposition of Spallation Polymer Particles Flying in Polymer Ablated Arcs

2015 ◽  
Vol 135 (11) ◽  
pp. 681-687 ◽  
Author(s):  
Takuya Nakagawa ◽  
Tomoyuki Nakano ◽  
Yasunori Tanaka ◽  
Yoshihiko Uesugi ◽  
Tatsuo Ishijima
Keyword(s):  
Numerical Simulation ◽  
Thermal Decomposition ◽  
Polymer Particles

Sensorineural hearing loss as a problem of modern otolaryngology (review)

2020 ◽  
pp. 50-64
Author(s):  
Anton Zhuravlev
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Social Activity ◽  
Healthy Person ◽  
Sensorineural Hearing ◽  
Significant Part ◽  
The World ◽  
Preservation And Restoration

The article presents an overview of factors that contribute to the development of sensorineural hearing loss, and approaches to solving this problem. Considering that we receive a significant part of information about the world through sound signals — and a healthy person is able to recognize over 400,000 different sounds —preservation and restoration of the patient’s hearing is of particular importance for maintaining social activity in modern, informational conditions of the society development.

ANALYSIS OF WORK ON NANOSTRUCTURED MATERIALS IN ORTHOPEDIC DENTISTRY UNDER THE DIRECTION OF PROFESSOR E.S. KALIVRADZHIYAN

2020 ◽  
pp. 8-13
Author(s):  
Жанна Владимировна Вечеркина ◽  
Наталия Владимировна Чиркова ◽  
Михаил Анатольевич Крючков ◽  
Виктор Сергеевич Калиниченко
Keyword(s):  
Nanostructured Materials ◽  
Dental Materials ◽  
Physical And Mechanical Properties ◽  
High Strength ◽  
Barrier Properties ◽  
Working Time ◽  
Polymerization Process ◽  
High Tech ◽  
Acrylic Polymer ◽  
Removable Plate

Развитие технологий, основанных на использовании низкотоксичных материалов, позволит в скором будущем начать их применение в медицине. Применение наночастиц серебра, меди, кремния, цинка, титана, кобальта в качестве модифицирующей добавки позволит оказать активное влияние на структуру исходных материалов и изменение их свойств, а именно улучшение физико-механических, физико-химических и токсико-гигиенических свойств материалов. Наноразмерные частицы кремния, введенные в фиксирующие стоматологические материалы, приводят к улучшению физико-химических, физико-механических свойств кристаллизующихся материалов, а малая теплопроводность кремния может увеличить его рабочее время и снизить выделение тепла при реакции кристаллизации. Так как от этих характеристик зависит объем манипуляций, при фиксации ортопедических конструкций на опорных зубах целесообразно было бы привести рабочее время твердения к чистому времени твердения, что позволит увеличить объем манипуляций приготовленной массой без ухудшения ее свойств. Разработка высокопрочных, биосовместимых, высокотехнологичных нанопластмасс для базисов съемных пластиночных протезов является актуальной проблемой повышения качества жизни пациентов. Модификация наноразмерными частицами серебра, кремния акрилового полимера позволит улучшить такие физико-механические свойства, как ударную вязкость, прочность, температуростойкость, барьерные свойства, уменьшить усадку полимера на этапе полимеризации, в отличие от уже известных отечественных и дорогостоящих импортных полимеров. Наноразмерные частицы кремния, серебра являются сокатализаторами метилметакрилата, влияющими на уменьшение количества остаточного мономера после процесса полимеризации, тем самым повышая санитарно-химические и токсико-гигиенические характеристики полимера. Все вышеизложенное позволило сформулировать цель исследований по наноструктурированным материалам под руководством профессора …посвящается памяти профессора, д.м.н. Каливраджияна Э.С. The development of technologies based on the use of low-toxic materials will make it possible to begin their application in medicine in the near future. The use of nanoparticles of silver, copper, silicon, zinc, titanium, cobalt as a modifying additive will make it possible to actively influence the structure of the starting materials and change their properties, namely, improve the physicomechanical, physicochemical and toxicohygienic properties of materials. Nanosized silicon particles introduced into fixing dental materials lead to an improvement in the physicochemical, physicomechanical properties of crystallizing materials, and the low thermal conductivity of silicon can increase its working time and reduce heat generation during the crystallization reaction. Since the volume of manipulations depends on these characteristics, when fixing orthopedic structures on abutment teeth, it would be advisable to bring the working time of hardening to a pure hardening time, which will increase the volume of manipulations with the prepared mass without deteriorating its properties. The development of high-strength, biocompatible, high-tech nanoplastics for the bases of removable plate prostheses is an urgent problem to improve the quality of life of patients. Modification of acrylic polymer with nano-sized particles of silver and silicon will improve such physical and mechanical properties as impact strength, strength, temperature resistance, barrier properties, and reduce polymer shrinkage at the stage of polymerization, in contrast to the already known domestic and expensive imported polymers. Nanosized particles of silicon, silver are cocatalysts of methyl methacrylate, affecting the reduction of the amount of residual monomer after the polymerization process, thereby increasing the sanitary-chemical and toxic-hygienic characteristics of the polymer. All of the above made it possible to formulate the goal of research on nanostructured materials under the guidance of the professor …dedicated to the memory of the professor, d.m.s. Kalivrajiyan E.S.

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