不同的等规和共规丙烯/α-烯烃共聚物的SSA研究及其在γ辐照下的结构变化

IF 7.4 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability Pub Date : 2025-09-08 DOI:10.1016/j.polymdegradstab.2025.111658

C.J. Pérez , Angel J. Satti

{"title":"不同的等规和共规丙烯/α-烯烃共聚物的SSA研究及其在γ辐照下的结构变化","authors":"C.J. Pérez , Angel J. Satti","doi":"10.1016/j.polymdegradstab.2025.111658","DOIUrl":null,"url":null,"abstract":"<div><div>The Successive Self-nucleation and Annealing (SSA) technique was used to investigate the morphological structure of isotactic and syndiotactic metallocene-catalyzed polypropylene (iPP and sPP) and their random copolymers with α-olefins (1-hexene and 1-octadecene). This study explores how tacticity, comonomer incorporation, and side chain length affect lamellar formation and crystalline fraction distribution. SSA allowed a detailed deconvolution of lamellar populations, revealing that iPP favors longer ordered sequences and thicker lamellae, whereas sPP exhibits lower crystallinity and thinner lamellae due to its distinct stereoregularity. Copolymers with similar comonomer contents showed comparable SSA profiles, yet those with longer side chain branches presented reduced crystalline fractions in thicker lamellae, indicating a clear influence of short chain branching on the crystallization process. Even low crystallinity copolymers demonstrated measurable lamellae formation at shorter crystallizable sequence lengths. Additionally, SSA proved effective in detecting morphological changes induced by gamma irradiation, revealing that chain scission, branching, and crosslinking alter the distribution of crystallizable sequences—effects that conventional DSC could not resolve. Overall, SSA demonstrates high sensitivity for distinguishing subtle structural variations in metallocenic PP and its copolymers, providing valuable insights into the relationship between molecular structure, crystallinity, and processing modifications.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"242 ","pages":"Article 111658"},"PeriodicalIF":7.4000,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"SSA insights into different metallocenic isotactic and syndiotactic propylene/α-olefin copolymers and their structural changes due to gamma irradiation\",\"authors\":\"C.J. Pérez , Angel J. Satti\",\"doi\":\"10.1016/j.polymdegradstab.2025.111658\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>The Successive Self-nucleation and Annealing (SSA) technique was used to investigate the morphological structure of isotactic and syndiotactic metallocene-catalyzed polypropylene (iPP and sPP) and their random copolymers with α-olefins (1-hexene and 1-octadecene). This study explores how tacticity, comonomer incorporation, and side chain length affect lamellar formation and crystalline fraction distribution. SSA allowed a detailed deconvolution of lamellar populations, revealing that iPP favors longer ordered sequences and thicker lamellae, whereas sPP exhibits lower crystallinity and thinner lamellae due to its distinct stereoregularity. Copolymers with similar comonomer contents showed comparable SSA profiles, yet those with longer side chain branches presented reduced crystalline fractions in thicker lamellae, indicating a clear influence of short chain branching on the crystallization process. Even low crystallinity copolymers demonstrated measurable lamellae formation at shorter crystallizable sequence lengths. Additionally, SSA proved effective in detecting morphological changes induced by gamma irradiation, revealing that chain scission, branching, and crosslinking alter the distribution of crystallizable sequences—effects that conventional DSC could not resolve. Overall, SSA demonstrates high sensitivity for distinguishing subtle structural variations in metallocenic PP and its copolymers, providing valuable insights into the relationship between molecular structure, crystallinity, and processing modifications.</div></div>\",\"PeriodicalId\":406,\"journal\":{\"name\":\"Polymer Degradation and Stability\",\"volume\":\"242 \",\"pages\":\"Article 111658\"},\"PeriodicalIF\":7.4000,\"publicationDate\":\"2025-09-08\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Polymer Degradation and Stability\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0141391025004872\",\"RegionNum\":2,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"POLYMER SCIENCE\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Polymer Degradation and Stability","FirstCategoryId":"92","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0141391025004872","RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"POLYMER SCIENCE","Score":null,"Total":0}

引用次数: 0

摘要

采用连续自核退火（SSA）技术研究了等规和共规金属茂烯催化聚丙烯（iPP和sPP）及其与α-烯烃（1-己烯和1-十八烯）的无规共聚物的形态结构。本研究探讨了弹性、单体掺入和侧链长度如何影响片层形成和晶体分数分布。SSA允许对片层种群进行详细的反褶积，揭示iPP倾向于更长的有序序列和更厚的片层，而sPP由于其独特的立体规则性而表现出更低的结晶度和更薄的片层。共聚单体含量相近的共聚物表现出相似的SSA谱，但侧链分支较长的共聚物在较厚的片层中呈现出较低的结晶分数，这表明短链分支对结晶过程有明显的影响。即使是低结晶度的共聚物在较短的结晶序列长度下也能形成可测量的片层。此外，SSA在检测伽马辐射引起的形态变化方面被证明是有效的，这表明链断裂、分支和交联改变了可结晶序列的分布，这是传统DSC无法解决的影响。总的来说，SSA在区分金属PP及其共聚物的细微结构变化方面表现出很高的灵敏度，为分子结构、结晶度和工艺修饰之间的关系提供了有价值的见解。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

查看原文本刊更多论文

SSA insights into different metallocenic isotactic and syndiotactic propylene/α-olefin copolymers and their structural changes due to gamma irradiation

The Successive Self-nucleation and Annealing (SSA) technique was used to investigate the morphological structure of isotactic and syndiotactic metallocene-catalyzed polypropylene (iPP and sPP) and their random copolymers with α-olefins (1-hexene and 1-octadecene). This study explores how tacticity, comonomer incorporation, and side chain length affect lamellar formation and crystalline fraction distribution. SSA allowed a detailed deconvolution of lamellar populations, revealing that iPP favors longer ordered sequences and thicker lamellae, whereas sPP exhibits lower crystallinity and thinner lamellae due to its distinct stereoregularity. Copolymers with similar comonomer contents showed comparable SSA profiles, yet those with longer side chain branches presented reduced crystalline fractions in thicker lamellae, indicating a clear influence of short chain branching on the crystallization process. Even low crystallinity copolymers demonstrated measurable lamellae formation at shorter crystallizable sequence lengths. Additionally, SSA proved effective in detecting morphological changes induced by gamma irradiation, revealing that chain scission, branching, and crosslinking alter the distribution of crystallizable sequences—effects that conventional DSC could not resolve. Overall, SSA demonstrates high sensitivity for distinguishing subtle structural variations in metallocenic PP and its copolymers, providing valuable insights into the relationship between molecular structure, crystallinity, and processing modifications.

求助全文

通过发布文献求助，成功后即可免费获取论文全文。去求助

来源期刊

Polymer Degradation and Stability 化学-高分子科学

CiteScore

10.10

自引率

10.20%

发文量

325

审稿时长

23 days

期刊介绍： Polymer Degradation and Stability deals with the degradation reactions and their control which are a major preoccupation of practitioners of the many and diverse aspects of modern polymer technology. Deteriorative reactions occur during processing, when polymers are subjected to heat, oxygen and mechanical stress, and during the useful life of the materials when oxygen and sunlight are the most important degradative agencies. In more specialised applications, degradation may be induced by high energy radiation, ozone, atmospheric pollutants, mechanical stress, biological action, hydrolysis and many other influences. The mechanisms of these reactions and stabilisation processes must be understood if the technology and application of polymers are to continue to advance. The reporting of investigations of this kind is therefore a major function of this journal. However there are also new developments in polymer technology in which degradation processes find positive applications. For example, photodegradable plastics are now available, the recycling of polymeric products will become increasingly important, degradation and combustion studies are involved in the definition of the fire hazards which are associated with polymeric materials and the microelectronics industry is vitally dependent upon polymer degradation in the manufacture of its circuitry. Polymer properties may also be improved by processes like curing and grafting, the chemistry of which can be closely related to that which causes physical deterioration in other circumstances.